You mentioned that the tires are not original. That's good. But, did you check the DATE CODE? It should be molded into the sidewall. I have read too many stories of "good looking" tires, with old dates, having blow-outs.
Before I learned about tire dating, I learned this the hard way on a 10-year old cargo trailer. The trailer had spent a lot of its life stored in a climate controlled building and the tires looked great. Tread was real good. Low mileage on the tires. We were towing the trailer down the Interstate doing 60-65 when suddenly it "felt funny." Immediately pulled onto the shoulder. Got out to see that the tire was in shreds. Limped to the next exit. Fortunately it had a Walmart with an auto department. I parked next to their building and we got out to take a look. What we had not noticed the first time was that the entire aluminum fender had been ripped off and was no where to be found. Yup, we looked at the shredded tire on the side of the road before and none of us (3 guys) noticed that the fender was gone.
Fortunately no one was hurt. We purchased a pre-mounted tire on a new rim (saved old rim for future spare) and got on our way. Upon return home I replaced the fender and the running lights on the fender. We got lucky!
Moral of the story: check the dates. RV tires typically "age out" instead of "wear out."
Sounds like you've got everything else under control. And, got a lot of work done in a very short period of time. Impressive.