Well, I guess I should have expected it, this being the class C forum and all, but I sometimes wonder if those who claim how much easier class C's are to work on than class A's have actually ever tried it on both?
I've owned 2 class C's, both on E350 chassis, and they were both a nightmare to work on. The doghouse only exposes the rear 1/2 of the engine, the small hood only exposes the top front 1/4. The remaining 1/4 is blocked, top and sides, by the firewall, too far forward to reach from the back and too far back to reach from the front. Have fun getting the mid-point spark plugs on either side (one of my Cs actually had a section of the shock tower cut out with an acetylene torch by a previous owner to facilitate access to that plug). The other problem that the van cabs have (that trucks don't) is the fact that the floor is surrounding the rear of the engine, at the mid-engine level. Try replacing a broken exhaust manifold stud (a common occurrence) with barely 4" of clearance between that manifold and the gas pedal. Perhaps the newer Fords are better, but there is still the matter of the floor level being at about mid-engine level and the passenger compartment area for "feet" being next to the engine rather than above (like a class A) or behind (like a truck). That does not lend itself to easy engine access.
Working on MY class A (Workhorse chassis) on the other hand, is like stretching out in a large open air garage. The easily removed doghouse (one quarter-turn allen bolt) exposes the entire top of the engine from just behind the radiator to the trans, and both sides are fully accessible from the large wheel wells without even removing a tire; all sparkplugs and coils are easily visible and accessible, as are all of the exhaust manifold studs. The entire floor is above the engine, not at the mid-engine level. Oil change? I can literally sit nearly upright underneath with full access to the drain plug and filter, as there is no other "stuff" closely surrounding the engine/trans and the floor is higher than the C. Belts and hoses are a bit of a pain, but certainly not much worse than my class Cs.
Obviously, some class A's may be worse, but all class C's have tight working space around the drivetrain. The same blanket statement cannot be made about class A's.