Re: about to buy a Thor 18' Freedom spirit
(It wasn't me, DL) What shape is the Thor in? Pull the wheels off and check the brakes. If it has been sitting for a long time they might be bad or in need of lubrication. Have to use a brake controller anyway. Pulling is only half the battle. Stopping is the other. Use a weight distributing hitch and sway bar. Save some grief if you get in a windy condition or passed by a semi. Plus check the rubber.
Hook up the trailer at home to water and electricity to make sure everything works. No fun to get to the campground to find you don't have a water heater or the toilet leaks. I would also rinse and dump all of the tanks. Fill them with water and take the trailer to a dumping station. And I would check the propane tanks. The new tanks have to have an overfill preventive valve in them and if yours doesn't no one is going to refil them. Might find them cheaper at home than out on the road. You can empty the old ones first though.
Just a few thoughts. Make up a checklist of things you have to do before leaving, when setting up camp, and when getting ready to come home. You might save the television attenna for a while.
Good Luck.