Call FMCA. You'll need to join them to use the program, but buying tires thru the program could save you more then enough to cover this.
And it's not just Michelins. Because of the large backorder on Michelins right now, suppliers will not be seeing them flowing to if lucky the 1st to 2nd week of September, also consider BG Goodrich. They're owned by Michelin, and qualify for the Advantage Program. I just chose 2 BF Goodrich ST230 to replace some damaged tires (I can't wait for Michelin.). It's a good Tier 1 tire, and it was a much lower price the the XZY3 tire that the shop could still find 2 of in my size (But this is more of a regional tire, and was not something I would have considered anyways.).
In your size, probably the XZA3 would be the appropriate Michelin for your coach. One other way to go, is 2 XZA3 on the steers, and BF Goodrich ST230's on the rear. But, only if you can wait for the Michelins to start flowing again.
And be warned, at least in the Denver area where I'm passing thru and needing to do all of this 'now' (pot hole damage two tires), the shortage of Michelins has rippled over to a shortage on other Tier 1 tire suppliers. I had several days of calling around, and were given options time in again for regional or heavy duty trucking tires. The few tires that were appropriate, IMO, for RV and highway usage - had born on dates going back to 2014. Don't one to spend this kind of money, and get too old of tires to start with (one gent wanted to sell me tires with a week code of 12, from 2014 (1214) That is March or fist of April of 2014. Said it was the install date that mattered, not the born on date. Not to me and my wallet
Best of luck to you,