I would check with the manufacturer of your smaller class A. Reason I say that, is most gas class A homes consist of an incomplete vehicle typically made by chev or ford, and MAY or may not have frame extensions welded on.
You can reinforce the hitch all you want, but if those frame extensions cant handle the downward force exerted by the added weight of a complete bike, you may end up causing some serious and likely permanent damage to your new, small coach.
On the other hand, the frame extensions may be re-enforceable themselves, and might be a simple case of that.
Check with the manufacturer (to save their ass-ets they may just decline to comment), and with a reputable fabrication/welding shop for a second opinion.
With regards to towing... a good option to consider is a AWS suv. While it does weigh considerably more than a 'small car' it will actually weigh less on the frame because AWD vehicles must be towed with all 4 wheels rolling.
http://www.hitchsource.com/11-14-ford-edge-includes-ecoboost-and-adaptive-cruise-control-blue-ox-tow-bar-baseplates-p-32759.html
This is an example of the towing hardware for my 2014 ford edge. Works great, no damage to toad or coach.
CHECK WITH VEHICLE MANUFACTURER ABOUT VEHICLE SPECIFIC REQURIEMENTS FOR THIS. IN MY FORD I HAVE TO STOP AND RUN THE ENGINE TO COOL OFF TRANS FLUID AFTER 6 HOURS OF DRIVING.