@FourtunateSons First your stock just went up in my eyes for responding quickly. Sorry but it is not uncommon here to see one and done posts.
I have owned more than a dozen boats including 2 vintage Hatts. Your RV experience will be helpful but as noted adding salt water and many other factors make boating significantly different.
I would start with a list of items like this:
1) Budget. What can you comfortable afford to buy and maintain? What is your cruising budget? Not based upon cost but what can you comfortable maintain.
2) Even though it will change, plan out your first 3 years. Year 1 will mostly be spent in prep after you buy the boat. Even if it is 100% ready you have a lot of work to do to transition from land to water.
3)Once you have this 3 year plan do a realistic cost assessment. Compare this to item #1.
4) What assumptions did you make to come up with #3. How much time in marinas. How many trips "home" or to visit family? Is that aligned with family expectations?
5) What is your plan after boating? What happens if health or family issues force a change in plans. Role play as a family and stress test against your financial plan.
6) Get all the time with experienced boaters you can. Join a local club or volunteer on boats. I just had a couple join me from San Diego to San Francisco. Being east coast boaters they gained a new perspective on West coast cruising. Night and Day. Take classes. Volunteer to crew on some passages.
7) Family first. A 1 year RV trip is similar but different from several years living aboard where you have now severed the ties to "home". Male plans A, B,C...
There are probably another 100 considerations but at least these are some concrete topics that can get you started.
There will be some snarky remarks but mostly experienced and helpful folks.