I drove back and forth across the country many times in a '93 bounder 28T riding on the hated P30 chassis. Some days I drove 700 miles without discomfort, stopping for a short stroll once in awhile. The P30 was a very smooth riding chassis. You will be driving a rig decades newer on what others say is a great Ford chassis.
We put 200k miles on the engine and transmission without any problems except for some bolt on outside the engine items. This engine is still running great. If you drive gently and keep up your maintenance schedule the gas engine will last. I have met other gas owners with similar results. We have talked about the stories of engine replacements at half the miles we had, and some asked "What the hell are they doing with their engines". One fellow I met that was a former GM mechanic, said that he has worked on 454's where the bottom end of the engine went 350k miles without rebuilding. My pickup went 285k without rebuild, it was still running when sold. The gas engines if used correctly, are just not as fragile as people are led to believe, after absorbing all the anecdotal stories off the web.
Owners without problems do not post much here and the membership that does post on this site are a fraction of present rv users. I have read quite a few posts from former dp owners, that had changed over to gas and were quite satisfied.
If you are leaning toward a newer gas model because of price, don't let the gas engine scare you off. Then again if you would really prefer the advantages of dp, there are some astonishing used bargains, retail or especially in the private market.
Kevin n Chriss - 2015 Newmar Bay Star-
1993 Fleetwood Bounder -The Flounder-