my 2007 Winnebago View had a Coleman heat pump from the factory. It was wired so that the thermostat controlled it and the furnace. If you selected more than a 2 degree differential from the room temp, the furnace came on in addition to the heat pump, so I was always careful to creep the temp up in stages. I used it a couple of times when staying at Ft Pickens in December. Needed heat and it was better than burning gas.
As Gary noted, you might not have a thermostat wire cable with enough conductors and have to pull new wires. Beyond that, its 4 bolts to remove the existing unit, and 4 bolts to install the new unit, hook up wires and install the air intake/filter and thats it.
I prefer to cover the roof with moving quilts (Harbor Freight) then quarter inch plywood to prevent any damage to the room membrane or whatever surface it is. The units are heavy, like a good sized window A/C. You need a scissor lift, forklift, scaffold, or overhead hoist and proper sling. If you are strong, and foolish enough, it could be walked up a ladder with help, but I would never consider trying that.
You ever convert? I have a cometic that has the option for heat pump and trying to find someone to do it and the cost?
The "conversion" is the cost of a new unit, and the cost of changing it out with the old one. You might get a few bucks selling the old one.
I just replaced the 27 year old Trane 1200 3 ton in my house with a Bosch 4 ton 18 SEER and Bosch air handler, all inverter driven variable speed compressor and fan. So quiet you cannot hear if even when standing next to it. Will pay for itself in about 5-7 years in electric savings.
Charles
