I second the TT idea. The worst thing for a motor vehicle is letting it just sit. It will certainly help the engine to be started and run for at least a 1/2 hour or so now and then but that doesn't roll all the bearings and sling oil in the drive axle. I've seen ring gears heavily rusted on the portions that are not laying in the gear lube. A vehicle needs to be driven.
If you are staying in one place you dont need a truck. If you do need to move to another park, getting a pick up to move a TT is cheap and easy. The worst that will happen to a TT from not moving is tire, wheel bearing and brake issues which are all low skill repairs. Most RV parks have poor wifi. The most expensive RV issues are Refrigerator, Air conditioner, furnace, water heater and water pump. The fig issue is expensive if you replace it with a propane model, if you replace it with a residential it would be about $300 to $400.
Whatever you decide on, DONT leave the black tank valve open all the time. Let the tank fill up before dumping. Use a generous amount of water when flushing the toilet. The black tank monitor is useless.
Be extremely careful when shopping for any RV as water damage is the number one issue. Any musty smells are just about a sure sign of water damage. Check the roof now and then for caulking issues. Seal around all the windows, marker lights etc and do routine checks. You cant be too careful about water. People will try to mask the damage. If you are unsure of your inspection abilities get help.
A slide will make the living area a whole lot nicer. They can have issues with water or mechanisms but you wont be running it in and out a lot.