All 4 tires are 215/65R16C....is that a problem?
I run 205/16's all the way around in the winter. There's plenty of room on the front wheel wells, so I'n pretty sure 215's will go all the way around. My '05 QD came with 215/16 on the rear. I read somewhere that Winnebago moved up to that size because smaller tire had a tendancy to blow on the rear axle.