Ron---
I don't participate in this forum anymore since I think every topic that can be talked about has been covered about 10,000 times before, but your basic question is an excellent one and is something every boater has faced at one point or another. So although I've said all this before ad nauseum perhaps it will be of some benefit......
Owning a boat is a never-ending expense. The purchase price of the boat is only the down payment for the boat. Something a surprising number of boat buyers overlook is the ownership cost of a boat. Ownership cost consists of: insurance, moorage, annual registration fees (if applicable), electricity (uniess the moorage fee includes this), fuel, servicing, maintenance, upgrades, and repairs. In other words, everything but the purchase price/payments on the boat.
A very rough, but basically accurate, rule of thumb for calculating annual ownership cost is ten percent of the purchase price of the boat per year. So if you buy a boat for $100,000 you should figure on spending about $10,000 per year on ownership cost the entire time you own the boat.
As I said, it's a very rough rule of thumb. A brand new or nearly new boat will not have the maintenance, repair, and upgrade costs of an older boat, at least not for a number of years, so the annual ownership cost will be less than ten percent, perhaps a lot less. On the other hand, an older boat may end up needing a lot of things done to it and the annual ownership cost can easily exceed the ten percent figure, at least in some years.
Doing as much of the servicing, maintenance, and repair work on the boat yourself is one way to reduce that ten percent figure. And some years not much will have to be done so the ownership cost will be lower, perhaps much lower. Other years you may need to replace a shaft or install new engine mounts or have a new exhaust system put in, and the ownership cost for that year may exceed the ten percent figure, perhaps by a lot. But on average, with average boats, ten percent per year is a pretty accurate number to use for initial budgeting purposes. It has certainly been the case with our older Grand Banks, and we try to do as much of the servicing, maintenance, and repair ourselves as possible.
Way back in the 1960s I read a fictional story in Boy's Life Magazine about a young man who came to a New England seaport town and decided he wanted to buy a sailboat. Another young man, a local boy who was an expert sailor, gave him a piece of advice which was, "Buy the smallest boat you can afford." By which he meant that for x-amount of dollars, the smaller a boat one buys, the newer it will be, or the better shape it will be in, which generally amounts to the same thing. So you get a better boat for the money and you get a boat that will not need a ton of work just to make it usable.
Needless to say, the newcomer did not follow this advice and bought the largest sailboat his budget could accommodate. The boat was a disaster and when combined with the newcomer's lack of sailing experience the inevitable end result was the rather dramatic loss of the boat.
"Buy the smallest boat you can afford" is a simplistic statement designed to stick in your mind--- it obviously has in mine. However it needs a bit of interpretation. You certainly don't want to buy a boat that's too small for your needs. If what you want to do, the number of people you want to carry, etc. dictate a 42 foot boat, then buy a 42 foot boat. But don't buy a 50 foot boat just because you find one that fits your purchase budget if the right 42 foot boat will meet your requirements.
The other thing I feel is important to do is to forget about makes and models of boat at this point. Define what you want to do with the boat first. Ask yourself every question you can think of that applies to what you want to do with the boat and how you want to use it. How many people on board? How many heads/toilets do you want? What kind of waters are you going to cruise in? Are you going to be going through a lot of locks? If so, what kind of deck access do you need to set fenders and lines? Are you going to anchor out or marina-hop? What kind of galley do you want, propane or electric? How fast do you want to go? What's the weather going to be like where you cruise? Do you need air conditioning? Will you need to deal with a rainy climate a lot? Do you prefer one engine or two (either way has its advantages and disadvantages--- there is no right or wrong one-size-fits-all answer here). Are you going to have pets on board? Kids? What does your boating partner want out of the experience? What will make her confident and happy out on the water. (Example--- my wife is more confident and relaxed with two engines under the floor instead of one even though we used to charter a single engine boat and she enjoys flying a single engine floatplane into remote territory in SE Alaska and BC. So for us, this makes a twin-engine boat a requirement despite the higher fuel, service, and maintenance costs-- having a relaxed and confident boating partner is worth whatever it takes to achieve this.)
The more questions you can think of to ask and answer, the better the definition of your boat requirements will be.
Once you have asked and answered all these questions, you will then have the data you need to start narrowing down the type of boat that will best suit your needs. It may not be a "trawler-type" boat at all. It might be a cruiser-type boat (Bayliner, Tollycraft, etc.). It might even be a trailerable boat. Or it might be a trawler-type.
And never, never, get into boating with the idea that a boat is some sort of investment unless you're buying something like a restored vintage Gar Wood or Hacker Craft. There are exceptions to this and one can lease-back a boat into charter and perhaps cover the ownership costs and whatnot. But for the most part for most people a recreational boat is a toy and as such you will always lose money on it. Sure, in 1998 we paid more than twice as much for our Grand Banks than what it sold for brand new in 1973 but that's just the actual dollar amount. In terms of dollar value, we paid significantly less than the boat had been worth new. In 1973 a new GB36 cost about $40,000 equipped. In 1998 a new GB36 cost well in excess of $300,000 equipped. We bought our boat with the intention of never seeing one dime out of it at the end. All the expenses--- new exhausts, shafts, radios, GPS plotters, engine mounts, etc., etc., etc.--- are simply the cost of being able to enjoy the boat.
One thing we did when we went to California to inspect, sea trial, and have surveyed the boat we eventually bought was to take a good friend with us who had spent thirty-plus years in the marine propulsion/generator industry. He knows boats like ours backwards and forwards and, most important, could have cared less if we bought the boat or not. My wife and I were totally new to this type of boat and short of an electrical panel actually being on fire, we were not experienced enough to accurately evaluate boat systems and construction ourselves. But our friend was. The money we spent on his airfare and lodging for a couple of days was probably the best money we've ever spent as his presence helped us properly evaluate the boat and then have confidence in our final decision. I don't know if you know anyone in a similar position, but if you do a person like this can be a real asset.
Finally, never forget that this whole boating thing is supposed to be fun. If you buy the wrong boat, or get in over your head with a boat that needs a lot of work, or if you get a boat that proves to not really do what you want it to do, your boating experience will not be all that enjoyable and could end up being a giant-- and expensive-- frustration. So don't rush it, take plenty of time to truly evaluate what you want a boat to do for you, and then shop carefully. There are a ton of boats out there, they're not going away, and you will always have a huge selection to pick from. Talk to boaters who do what you are hoping to do. This will help you get a realistic idea of what you need in a boat and will start generating a short-list of potential boat makes and models that could fit your needs. When the day comes you think you've narrowed your search down to a particular boat, spend the money for hull and engine surveys by the best surveyors for this type of boat you can find. This usually means two surveyors as most of them tend to specialize in hulls/structure/systems or engines.
Whether you get the right boat or the wrong boat, either way it's going to cost you a bunch of money to buy it and own it. So better you take your time and do everything you can to ensure you get the right boat. Do it right, and you'll have the time of your life.