Wow, great job on paying attention to the details now. I hope you find it rewarding and relaxing once you get out there camping!
Re the OE tires - Some will tell you none are good, but I operate a little differently. Mine made it though a few trips with the original owner of my TT and one tire had abnormal wear. So I had that rotated out as the spare, and an alignment done at a HD Truck shop. No other signs of problems in the 1,800 towing miles since then.
I check on them multiple times each trip, and keep my speed under 65MPH. Any more signs of wear issues and I'll replace them. But if the current pattern holds, they'll make it to 5-years since MFG and get replaced then (regardless of wear).