OP here with an update. I went with the Goodyear Endurance, had them installed today. Since I couldn't see very much of the inside of the rims to find a stamp showing the PSI rating I called Jayco. They assured me that the rims were okay with the higher PSI for the D load rating of the new tires (the originals were LR C; 50 PSI).
I looked carefully for a PSI rating once a rim was removed but there wasn't one, BTW.
A local store had them in stock and I was able to get them for only a few dollars more than Walmart or Discount Tire Online would have cost, with less inconvenience. Plus the satisfaction of using a local merchant. Even though it was a chain, they still employ people locally, and I can deal with them for warranty or service issues, etc.
I am happy to report that the tires performed perfectly on the 1.25 mile drive back to my home!
Thanks to all on this great forum who took the time to contribute!