Will you be there living in it, or are we talking long term, unoccupied storage?
If it was me, I'd have the oil and filter changed before parking it. The gas tank should be filled with fresh gas, with the proper amount of stabilizer in it, and then run enough so that the unstabilized gas in the fuel lines is all used up and replaced by the stabilized gas.
Depending on when it was last done, consider flushing the cooling system and refilling it with fresh anti-freeze. Rubber hoses deteriorate over time just sitting there, so examine all your cooling system hoses and belts. Perhaps they need changing as part of the cooling system service.
How many miles on the vehicle? Automatic transmission? How long since the tranny fluid was changed?
You might also think about having the old brake fluid flushed out and replaced with new brake fluid. Brake fluid is hygroscopic, that is, it sucks water out of the air, and the water in the brake fluid can cause steel brake lines to rust.
You might also consider having the rear end fluid drained and replaced with fresh fluid.
The goal would be to have the rig ready to go as soon as you hook the batteries up and turn the key.
Oh, and find some way to protect the tires from uv rays, if possible.
As far as the onboard water system goes, if you won't be occupying the RV, it needs to be drained and winterized with RV anti-freeze. It goes without saying that the gray and black water tanks should be drained, and I would not leave water in the drinking water tank that long, you WILL get algae growth.
Regards
John
