Do not worry about the 10 year rule. There are not many that have it and if they do, they often let you in if the RV is well kept. Personally, I think they should just state that they have the right to refuse an RV over 10 years old if it is not well maintained. In my opinion, having a hard rule is just laziness on the part of the owners. They do not want to have to do the evaluation.
I also have no problem with the RV in the picture. There are horrible people in Prevosts and good folks in older RVs. Not all of us can afford to purchase a new RV every 10 years.