BandB,
Thanks for your detailed reply - here are is response to your questions:
1. I am thinking about a trawler because my priorities in a boat are safety/sea worthiness, reliability, comfort and reasonable operating costs. We like the idea of cruising - not speeding - to our destination. A trawler seems a good fit.
Some consider 12 knots speeding and others consider 60 knots.
2. I'm not sure what my neighbors have or how they use their boat or why that is relevant to my situation.
It's relevant because they may well have very similar needs to you. They cruise the same waters. For instance, there is a distinctive difference in the PNW which reflects conditions. What others in the area have chosen also gives you ideas. It's not that you must be like them, just understand what others have chosen in the same area. We're doing the loop right now in a boat that I'm unaware of anyone doing it in previously. However, we are well aware of what others have used and the recommendations of many.
3. Boats which offer an enclosed area to get away from the elements (rain and heat), have a head and some place to rest get my attention. Fishing or sports boats are not high on my list of wants in a boat.
So that seems a bit contrary to your initial post. I think now you're thinking more of a boat that would not be decent for 10 and would be less than ideal for 4 overnight, unsatisfactory for 6. Nothing wrong with that. One should choose a boat based on their 95% usage, not the other 5%. Take six along and someone sleeps in motel or you just throw air mattresses on the floor and act like kids. You might still look for salon furniture that one could sleep on if needed.
4. 10 - 20 kts/hr would be fine. I am not thinking about going into the deep sea so a retreat from weather might allow for a slower boat.
A lot of difference between 10 and 20 knots. It's much like the difference between Sea Ray and Kadey Krogen. I'd suggest at some point chartering. There are good charters near you of trawler type boats. Lots of Grand Banks but some other. You need to figure out if you can be happy with a boat that cannot go beyond 10 knots. Or do you need to have one that can cruise 15-18 knots. We have people on the forum who are very happy with 6 knots, many with 8 to 10 but then we have many who want the ability to go faster. If you're using it when time is limited, I'd strongly suggest you may want a little faster. Slow is for people in no hurry. Retirees are a perfect match. Well not my wife and me, but otherwise. However, when you have limited time on a Saturday or a weekend, getting somewhere quicker might be important to you.
5. Depth at the dock is ~10 ft; however we are on Smokehouse Bay and I believe it has some areas around 4 - 5 ft at low tide.
That will be a factor then. Now 4 to 5' is where a lot of boats hit in draft. If you need to be less than 4 you may be limited. If 5' is ok, then most boats you'd be thinking of are fine, although certain true passagemakers wouldn't be. You might ask your neighbors their draft and if they've had any problems.
6. We have direct access to the Gulf - no bridges.
I see that now on your initial post. I just missed it.
7. I am definitely looking at used and would like to come in under $100K.
You'll have no problem finding something that fits that range. Make sure you do have a good understanding of what annual maintenance might cost you.
8. Our experience with boats is limited, so ~30 ft would be what we are targeting.
That's probably a good idea. You will need to think about thrusters and if they're important as where as stabilizers. Most 30' boats don't have either. As you ease larger more do. At some point you might take some basic classes and then perhaps when you buy get a training captain to help. If you chartered with a captain and made it clear you were wanting to learn and make sure he's good for that, then even a pre-purchase charter will help you and give you an idea of what you know and what you don't.
9. Length of the dock from the front end of boat to first lift pylon is 18' 8". The lift pylons are 11' 8" apart. Its width is 13' 4".
Your lift dealer has specs that would indicate preferred sizes of boats and also could tell you how much the pylons can be adjusted and what they'll charge to adjust to your boat. It would seem to me 30' is probably a decent size with 9' overhang on each end and 12' between pylons.
10. I am leaning toward diesel due to safety, robustness of the engine and economy. I have some familiarity with diesel engines since we have a 4 cylinder turbo diesel running a backup generator for my house which I maintain.
Diesel has some significant advantages. However, there are many very good gas powered boats in the size you're looking. Some of those might fit your needs better. I just wouldn't dismiss it. As to safety you can search and see our arguments. As far as durability, with a late model boat and normal usage you won't be the one wearing a gas or diesel out.
I appreciate your comments - this has already help me with my thinking.