I have to agree with other posters--600 miles per year will not keep a motorhome from becoming a non-rolling structure!
Idling the engine will not warm up the transmission, lube up the other moving parts, keep the tires healthier, etc.
I do think a motorhome is a good idea but--take it out for weekend trips locally once a month or longer trips a few times a year. That will really get you into the lifestyle and stay informed as to how the rig is doing.
It sounds like a nice project no matter what you decided to do.
Some have mentioned a trailer but to tow it you will need a big truck and if the trailer will mostly just sit...there you are with a big truck that gets rough mpg to drive daily or also sit idle. With a motorhome you can just set up a small car to tow, travel toadless or have a second driver take the small car if you are going somewhere closeby.
Since we average 15,000 miles a year it is hard for me to imagine only 600 miles in a year. That is 2 or three days travel for us. As others have said your engine will not get any kind of adequate warm up unless you take it out and drive for 30 minutes to an hour at least monthly. The seals will set and dry out from lack of use and the tires will age faster than if you drive.
Get a trailer or a park model and rent a motorhome when you want to travel. That way you avoid the headaches of maintenance on the MH drive line and the generator which you will have little use for.
We love our 36 foot gas coach, but it is close to maxed out on power. I would not consider a bigger coach on a gas chassis.
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