As other have mentioned first check the integrity of the house before you start putting money into the chassis to safety make the drive home. If the roof has been leaking you could be looking at a major restoration work which might not be worth the effort or the cost. Spending $2000 for tires only to find out the roof and walls are rotted would be a bitter pill to take. More coaches die each year due to water leaks than engine failure.
Work with the camp ground regarding getting the coach road worthy. Check everything particular the brake calibers. Sitting than long the caliber pistons may have rusted in place or the master cylinder seals are leaking. And start shopping for a road side emergency service contract before making the drive in a rig that hasn't seen the road in a while.
Good luck and I hope you have a diamond in the ruff that just needs some TLC.