Check you TV and TT battery's distilled water levels. Should be just to the bottom of the tube.
Make a visual check of your TT tires along with pressure check. Tires often get a slight bulge or squiggly tread when the belts start to separate.
Open access panels and check faucet connections for leaks. Those slow weeping leaks will slowly become rotten wood.
When you get up there to check the roof's sealant once or twice a year, peek under the a/c shroud at the drain hole. If it clogs, drainage will be in the ceiling and more rotten wood. If it's hot and humid and your a/c isn't dripping over the side of the TT, check the drain hole.
I like to put a drop of Mobil-1 5w-30 on pivot points like the steps and leaf spring shackles. Keeps 'em quiet and hopefully they'll last longer.
A little slide seal lube is also a good thing.
Use your chocks. It doesn't take much of an incline to wave goodbye to your TT.