Since your coach is new Ford probably installed tires from one of the big name manufactures, Goodyear, Michelin or maybe Firestone. You'll need to dig a bit on their web sites to find the pressure tables. Probably in the commercial truck section.
You'll find that the tires have a much greater weight capacity then the chassis axles so inflating to sidewall max will have you grossly over inflated.
GoodyearMichelinFirestoneAs a fall back Winnebago installed a placard near the driver's seat. The placard will list the recommended pressure based on the recommended tire size and the maximum axle capacity. More or less this is your maximum pressure if the coach is loaded to the maximum GVWR. Add 5 psi just incase your travel partner starts collecting rocks from all the places you visit.
The Long, Long Trailer