Hard to answer your question about placement of jack stands without actually looking under your coach. Mine is pretty easy in that there is heavy tubing structure associated with the hitch that I use in the back, and heavy structure associated with the generator bay that I use in the front. But my rig rides a good bit closer to the ground than most, so I appreciate the comment that your stands won't reach the frame rails.
You were absolutely correct that putting them under the axles or suspension components offers little protection if you lose air pressure.
Richard, Rhonda, Ty, and Alex
1995 Newell, 470HP Detroit Diesel Series 60