Probably one of the reasons that the E350 and E450 chassis are/were so good for Class C motorhomes is because they came from a basic design originally intended for the delivery van market - where one did not want to have truck floors too high off the ground so as to facilitate convenient loading/unloading of cargo. Hence, their fairly heavy cargo ratings combined with only 16 inch rimed tires - which keeps their profiles low.
If you move to the F450/F550 series for Class C motorhomes, you get the big step-ups into both their cabs and their coach areas... perhaps not too good for the folks with bad backs, hips, knees, etc.. In our case it's all the DW can do to get up into our E450 based Class C motorhome - even with it's automatic step and additional portable platform I set up outside.
We'll take an E450 motorhome over an F450 motorhome any day. HOWEVER, you add 4WD onto an E450 and it's height goes right up to about match that of a 2WD F450. Order an F450 with 4WD and the height of it's frame probably doesn't increase much over that of the 2WD version.
