Personally, I don't think the RV is a good way to go. That said, while you haven't lived in an RV yet, you at least have a reasonable understanding of the depreciation loss you're going to take.
I helped my son in law set up to work the oil fields out of Wyoming for three years, three more in North Dakota, and now he's back in Wyoming living out of a presidential 5er. As folks have mentioned, winter is hard on RV's as they really aren't designed for it, and his has taken a beating with only him living in it.
First make sure that you can get a lot in a park for full time, and if possible see if it's someplace you'll want to raise your kids. (Neighborhood applies to apartment as well) Fortunately, Heber is a nice area, not a lot of less than desirable neighborhoods. On the other hand, it's on the cold side of the mountain, where they have Olympic cross country ski courses, and where they do Ice castles in the winter. (Swiss days and the sheep dog championships ended this weekend) It's also a reasonable commuting distance to Provo, and the rest of the Salt Lake city valley.
You'll need skirting for the RV, heat tape for the water hose, insulation blanket for the sewer line etc. If possible, keep everything inside the skirting for plumbing and water if possible. Even with a good plumbing setup, you're going to potentially have issues, especially on windy days/nights with freezing of the external, or even internal plumbing.
Even the best RV's aren't very well insulated, thus the furnace will run almost constant when it's really cold. If possible, listen to the furnace running on the units you're interested in, see how you feel about living with the noise. Some, like my current Bighorn have done great things with quieting the noise. On the other hand, my old Timber Ridge by outdoors RV, while having a good, efficient furnace sounded like a small jet engine when it was running.
Rent a big Propane tank. Son in Laws propane consumption runs 700 to 900 gallons a year, so bulk tank and dependable delivery service is a necessity. Make sure you're plumbed propane wise in such a way that you can switch over to your internal propane tanks if needed.
Read up on and figure out what you'll do about condensation. Utah has very low relative humidity most of the time, especially in the winter. Trailers however, because of the poor insulation and small interior space suffer greatly from condensation in the when it's cold outside, especially when you have several people inside trying to live a normal life and doing things like breathing, showering, cooking etc.
Figure out what you're going to do about laundry. With a family, it may be hard to get used to having to hit the laundry mat on a regular basis. Some RV/trailer parks have laundry facilities on premise, some don't.
I didn't catch the ages of your kids, but keep in mind that 5ers are pretty lightly built and kids tend to tear them up quickly. It will especially be an issue in the winter when your kids are pretty much stuck inside a very small area trying to entertain themselves in the ways energy blessed children tend to do. For whatever reason, RV's are under 400 square feet in size, which isn't very big for a family unless you can spend most of the time outside somewhere.
Finally, as mentioned, many RV's have issues when new, and the RV dealers in the Salt lake city area tend to have long waiting lists just to get in for repair. I've had my current Bighorn for a month shy of a year now, and 3 months of that it has been on the dealers lot getting things fixed.
