Another thing to keep in mind is there are more and more RV parks with a strict limit on how new a coach must be. Doesn't matter if it was a million dollar Prevost and kept up well. Over the age limit and it doesn't get in the park. Depreciation on a coach is horrendous after you make the first drive off the lot and the age rules will cause a further significant hit if you keep it for a significant time. 
I retired in 2013. We didn't seriously consider an RV but we did buy a second home in AZ. At the time, a nearly new home wasn't a lot more money than a nice coach. Because we used the home enough every year, the gains when we cashed out were nice and also tax free. Any taxes on the proceeds from a sale of a 13 year old coach would not be much of a factor, I think ;-)