If you are talking about a park model that will be set up permanently, for me it would depend on where in the country it was to be located. Here in south Florida, the all electric park models are popular, as are houses, mine included. If I was to set up a park model in western Colorado, where we were living prior to moving to the swamp country, I would look at propane or natural gas, for heating, cooking, domestic water heating and a gas clothes dryer. In heavy snow country, the less frequent you have to fill is better IMHO. In western Colorado I saw many park models with twin 200 or 400 # propane tanks, dealer supplied. Some people used 300 to 500 gallon propane tanks so they could fill once or twice a year.
The KOA campground in Montrose Colorado, installed metered propane to the seasonal sites they have a few years back. The CG has a very large , several thousand gallon tank, to supply all the users. The campers, I talked to, that were using the metered gas were pleased with it. Probably other CGs in the area have metered as well.
Now if the OP is talking about the fifth wheel built by Nortland that they call a park model and promote for full time living, talk to the local dealer to see what other buyers are using.
joe b.
Stuart Florida
Formerly of Colorado and Alaska
2016 Fleetwood Flair 31 B Class A w/bunks
www.picturetrail.com/jbpacooper
Alaska-Colorado and other Trips posted
"Without challenge, adventure is impossible".