I hear ya...We were in boating for many years when my sons were younger. We had ski boats and eventually had a 47' Carver Aft cabin motor yacht, which we used to travel all over the Great Lakes. So, we're now retired and live in the Central Rocky Mountains...Like you, we want to get away from the snow, cold and winter after Christmas. So we purchased a used 2016 36' Open Range Journeyer model pull behind travel trailer. It has three slides, plenty of room for my wife, me and our pets to go when and where we want.
I use a 3/4 ton GMC diesel with Duramax transmission. Honestly, I get 11 miles per gallon when pulling the trailer. Note, my last boat got 9/10's of a mile
When on open highways and interstates, I cruise at 65 mph. Otherwise, I adjust the speed to the road conditions. When going south or east, we have to go over Monarch Pass at 11,400'. When I begin the climb up Monarch, I drop the transmission into 4th gear, set the cruise control at 45mph and away we go. When coming back down, I drop the transmission into second gear, apply the exhaust brake and rarely touch the brakes the whole way down. The pull behind we purchased is probably the largest one you would want to have before going to a 5th wheel. I like the trailer we purchased because it has lots of exterior storage, two central heat, and air units, a stand-up shower big enough for me, lots of closet space and an overall comfortable floorplan we felt was right for us.
When deciding on what RV to purchase, decide if you want a pull behind, 5th wheel, or an all in one motor coach such as a class A or a cab over RV such as a class C. As for specifically a class A or class C, we decided to avoid both because we didn't want to have to pull a vehicle behind us when traveling. If you don;t have a pull behind vehicle, then you're stuck in one place or you have to travel with your RV to wherever you want to go. Also, from my past experience in boating, letting a motor sit for long is never a good thing, so unless you're going to be traveling a lot, you don't want an RV such as a class A or class C that is going to be sitting idle for any length of time...Things will rot and break if not used. Then select the floor plan that meets your needs and wants. As in boating, most people go too small when purchasing an RV and then they find themselves upgrading the next year. We did that when we first started boating. We made sure not to do that when we decided to get an RV.
Once you have the right RV and floorplan, then, if needed, select the right tow vehicle, which is as critical if not more so than choosing the right RV. BTW, if you enjoyed boating, you will love RV life...