Question for Class A owners.

The only real challenge comes if for whatever reason they need to pull the engine. I’ve seen them go through the driver door (if there is one) or have to remove the windshield.

Have you worked on a new automobile recently???
I don't mean to be flippant but the new automobiles have so much stuff under the hood that it is impossible to see the engine without removing a lot of items. On both my Chevy and Chrysler, the space under the hood is so cramped that both of them have the battery in the trunk because there is no room under the hood in the engine compartment.
Motor homes are cramped for some repairs, and easy for others. If you go to a shop that specializes in RV, they will take care of you. Many medium and large truck shops will work on RV's. Motor homes have their own unique challenges, but so do the new vehicles that are on the road. The fact is that any problem can be taken care of. Some issues just take a little longer. :B

Inside there is a removable "dog house" on gassers. It usually offers decent access, sometimes great access - better than many other vehicles.

On a diesel pusher there is typically the rear closet floor doubles as an access hatch as well. A side radiator model allows awesome access from the rear as well. A rear radiator not-so-much.

Any vehicle presents it's own particular repair requirements. Front engine Class As (like the Ford 53) is no different. Just find a repair facility that works on them (there are many). I do my own mechanic work on my F53 and find things relatively easy. Either from underneath or remove the engine cover and work from the top.