Welcome ISM... may be a lot of info in that alone although a Prevost will not have that engine although it is one of the better ones. I hope to use my 04 Dynasty for another 13 years so you know where I'm going. You do not give us any info on how much you will use other than retired. By putting NA in RVing since... are you a virgin RVer? If so then "Twice the husband, on 1/2 the $$$$, and in 1/10th the space" may apply.
I always recommend buying more MH than you think you need... ONE TIME which is NOT what I did. Unfortunately the size is still debated with many still saying 36' max even for Full Time use . :S
If you will give us some more info on your intended use it would help.