I see everyone has gotten wrapped around the axle on tires. Sorry about the pun. Could not resist.
Now there is more to consider than tire size, though I recommend 22.5s.
Not all coaches, on a ford (V10) chassis, are created equal. Some ride better than others. Some have a lot of sway or wobble on turns. Some are on 22K, 24K and 26K chassis. Larger has better ride. Lengths vary from 29-40'. Some come with balsa wood and some with real wood. Some are laminated cabinets and walls. Some come with solid counters and some with laminate. Some have sound & heat dampening under the floor.
You are going to have to get into some, feel how you like floor plans and look at all the systems. For me, the floor plan is the most important factor. If y'all ain't comfortable, you wasted your money.
If you look and something is unclear or you don't trust what the salesman says (most don't) then come here and ask. Take pics and post them. Above all, take your time, unless you fall in absolute awe of a coach. There are a lot of sites with plenty of pics to do virtual tours.