I live on the west coast and have bought RV tires at Les Scwab because of excellent service and lots of locations. But I live mostly in AZ now and travel throughout the SW. Unfortunately Les Schwab does not have any stores in the SW so I now buy Goodyear tires from Discount Tires. During my travels I find that Discount Tires are usually located close to freeways and in many many locations. I generally do not buy tires based on price so I can't tell you if they have good deals; I can tell you that we have our tires checked weekly (for free) at Discount Tires when we travel and have had them service our tires when we needed them during our travel.
One thing to keep in the back of your mind when selecting tires for your rig... Availability.
I learned a painful lesson. I had put Maxxis tires on my rig and was very happy with them until one got nailed by road debris. I was out on the road and learned that practically no one stocks Maxxis tires (at least where I was) and would have taken 7-10 to order them in. However... Goodyear Marathons we're either in stock or I could have them within a day or so.
I ate the cost of the Maxxis and put Goodyears on. Solely because I want to be able to readily replace a bad tire within a reasonable amount time.
I just picked a set of Michelin - LTX® A/T2 LT225/75R16/E115R from Costco for $1250. I only have 25 miles on them so it's to early to comment on quality. I did noticed better ride quality than the 10 year old originals.