First off, congrats on your retirement!!! It's great.
Henry and Jim gave you some good ideas and it sounds like you may be well covered.
There are a few things I didn't see or may have missed reading, but consider these if you do not have already and they fit your situation.
1. A 1/2" drive torque wrench for the trailer wheels. If you have to change a flat, they need to be retorqued 3 times after changing the wheel. Even a $20 Harbor Freight one will work. Just make sure you an extension and a 13/16" socket.
2. While duct tape was mentioned, I'll go up to a specific brand/type as it gives more rugged service. A roll of 2" wide Gorilla tape. Since this product came out, it beats the normal run of the mill duct tape in about every way. Gorilla tape can hold a temporary patch in a rubber or metal roof tear for at least 6 months in the weather. It can deal with cracked skylights, ripped Darco, and most anything else that breaks on the camper as a temporary patch that tape will hold until you get home to fix it.
3. This next item is specific for you since you know how to deal with them. I carry a "fix it kit" of parts for my Dometic fridge. If there is one appliance that is going to die on you that can create great havoc, it is the fridge. The water heater, the water pump, the furnace, the range will all be a pain to work around, but if the fridge dies, that will be a big issue for us as we boondock on many of our long term travels and need to run on gas. I have a new dinosaur board, igniter, thermistor and the electrode. This all came about when my igniter died on a camping trip while boondocking and the fridge went out. While I have never since had to scramble to do a fridge fix on the road again, I now have the parts to overcome most things that will die that I can fix before the food thaws out. I know if I take those parts out of the camper, it will break down....
4. There is another one I'll mention. On your smaller camper this might not be a big a deal as on my larger camper. I always carry my Honda E2000 generator with me in the truck and a small 120 volt AC compressor capable of airing up a 100psi tire. My trailer and truck tires are 80 psi tires. I ended up with soft tire on the camper once at the campground and I had no compressor even though I had the genny. Well I'll tell you the short story, trying to find a gas station that can pump up an 80 psi tire that I can get my camper next to, is a challenge. After 5 gas stations I was ready to give up and then I saw a John Deere dealer. They bailed me out. Ever since, I bought and carry my own small compressor and the genny to run it.
5. For sure, make sure your trailer tire spare is in good condition. It too needs to be as good as the main trailer tires in age and build. The day you have a flat or blowout on the camper, you want that spare to be as good as all other trailer tires. Having a 7 plus year old spare is not worth much when you have to tow 100 plus miles to the next tire shop under full camper load. My spare gets changed every time I put all 4 new tires on the camper. After one deals with a blowout on the interstate, there is no question in your mind you have to have a top condition spare. The hope is, you never use that good spare, but the day you need it, you will be glad you have it.
6. I'll add one more thing, a hi reflective vest to wear in case you are on the side of the road fixing the truck or camper. Just fold it up and put it behind the seat. Dealing with a breakdown on the side of the interstate, you want to make sure all drivers can see you.
Your handy, and I'm sure will overcome all issues that fly up. Have a great trip and let us know how it goes. Remember, we like seeing pics of Sunlines in action!