Replacement tire for the Chinese OEM rubber

My 35 foot Keystone Bullet bunkhouse is less than 2 months old and has about 500 miles on the 205/75/R14 OEM tires................

I'm bummed that I don't have 15 inch wheels to begin with.

I suspect that looking for a coach with 15 inch tires is easier before you purchase something. Maxxis tires appear to be well received in all sizes so you can stay with the 14 inch and have some peace of mind. Virtually all rims are strong enough to go to a D rating but that is something to check into with your tire shop. Since tires are also rated on pressure it is possible you would never need the max pressure for a tire that has a D rating for your coach.