Wow Mikem.... If you weren't nervous before I'm sure you are now. Heck, I've been towing for nearly forty years and after reading all these posts all at one time I'm feeling edgy. Break it down and gleem the info you need. IMHO:
1- tires on trailer need to be checked and likely replaced.
2- check trailer brakes. May have issues from sitting a long time.
3- 7 pin might need cleaning/check running lights
4- set up weight distribution hitch correctly.
5- a transmission cooler is always a good idea if you don't have one already
6- keep it light. By that I mean no heavy cargo. Filling your gas tank is fine. Some water in the TT for flush and washing for comfort stops is fine. No need to carry full water or full waste tanks. Food, clothes, portable grill, couple of chairs, basic camp stuff.
7- get the feel of your rig. Take it slow and easy. Get the feel of stopping. That's the one that will feel strangest. Take you turns wide. Go slow. You'll get it.
8- stay in your camper overnight that's what it's made for.
9- you TV will get up to running temp within minutes and should stay pretty constant. Watch it for variations. When it's rising it indicates it's working harder. Ease up or maybe drop it down a gear. Roads incline and decline though they may appear level to the eye. On significant inclines ease up and /or drop it down a gear.
10- take it easy. Enjoy the ride and the adventure. You'll be fine. It's a pretty easy run and a great one to learn and gain experience on.