https://www.rvusa.com/rv-guide/2012-...-343rl-tr10628
Looks like 2012 High County's came with 235 80R 16 Load Range E tires with 6 inch wide wheels. As noted before, you need to confirm the wheel load capacity located on the back side of your RV's wheel. Hopefully they will be rated for 110psi and 3750#.
Sailun makes a tire that size in LRG that fits a 6 inch wide wheel that should work. They should be Speed rated L or 75MPH. Below is the link to the Walmart online tire:
https://www.walmart.com/ip/Sailun-S6...f4b676ee4476e7