I have the exact same coach only a 2003 year model. The label inside the coach calls for a 235/80RX22.5. I'm running Toyo 245/75R22.5 M154 tires. They are 8 years old, have around 50k miles on them and have no cracks and have given me absolutely no problems. They are however to the point where I plan to replace them this summer. I will be replacing them with the same tires. I like Toyos and you know what they say, "If it ain't broke don't fix it."
I hope this helps and good luck finding a good price. I'll be doing the same thing very soon.