Steve
Maybe this will help
https://beaveramb.org/forum/index.php/topic,7889.msg54809.html#msg54809The biggest Problem is to find a place to store them when traveling and of course the weight if you only use them at a home base that's great.
There are several manufacturers that have ramps for cars but most of those are too light and won't carry the weight your going to put on them
The other thing that needs to be considered is the height of the ramp as you still have to be able to fit it under the coach at normal ride height or less.
I use stacked sections of 2×10 to achieve the height I want but remember they have to be well supported on level ground or the coach weight will break them . As it is the 2x10s are only wide enough to properly center under one tire so usually set them up under the inboard duals .
Once I get my coach up on the ramps say about 6 inches I then can work under the coach( still not very comfortable) but safe enough.
Then I disconnect the rear ride height valves linkages and air up the bags to maximum ride height so I can then slip a pair of 10 ton Jack stands under the rear frame rails behind the axle to carry the coach weight after wards I air down the rear air bags settlings the coach on the stands and by using a bottle jack can lift the rear wheels off the ground to do wheel end and brake service work safely ,
If your working on replacing rear air bags you can put the rear end on jack stands as described above remove the wheels and inner fenders to gain full access this way you don't have to disturb the outer fenders creating possible paint work.
Hope this helps
Eric
If your doing air leak inspection on air bags it's best to be at ride height although I have found some harder to find air leaks in the air bags by disconnecting the ride height linkages and airing up the bags to increase the air pressure on those bags exposing more air bag and revealing leaks that where very small at the lower air pressure ( just remember to only air up to the suspension limit check straps)