Boaters say the three stages of life are sailboat, powerboat and RV. :B
We made the switch after 35 years of boating and find RV'ing in general and our 24' Class C in particular to be the best experience yet. The time spent boating makes us very comfortable in a smaller motorhome and the systems found in most RV's (plumbing, electrical etc.), are pretty much the same of those found on boats.
Consider Class C's in the 24-25' range, if you were happy on a boat these will be more than big enough and this size gives you far more options when it comes to mobility vs the larger C's. Good luck! :C