If you stay under 35' there is not need for a diesel engine. 36' to 38' it has to be built with an eye on saving weight as you are at the upper limit of what a gas engine will do. Newer V10's have 450 ftlbs and other than the Cummins ISB diesel engines everything else has 880+. My turbo will give me 100% power all the way to 10,000' and then it starts to drop off 2%/thousand.
For YOUR full time use Buy More MH than you think you need...ONE TIME. NOT LIKE ME. I know in a previous post the majority said to keep it small, but having started with a 36' used DP it did not take long to realize that was not true so went to 40 and now 42. Sure it's harder, but not impossible especially with all the info on the internet BUT do not expect to find a big site on Friday afternoon.
We will do 2-3 months out West boondocking five days/week without reservations. No problem finding a big site late Sunday afternoon or Monday usually where we want to stay or within 10 miles. We move and resuppply on the weekends unless it's a holiday weekend then we may stay put.