Ok, there are three things that often need to be done to a motor home, This is NOT in likelyhood order
Sway: Side to side rocking of the body, Think of fans at a rock concert holding up their lit lighters swaying side to side...
Solution: Sway bar.. you have one but a better one may improve.. LEAST likely
WAG: with leaf spring and solid (one piece) axles the body can move, slightly, right and left, Often one end moves one way while the other moves the other, This gives the impression you are NOT going down the straight and narrow, even if you are.. You are kind of like the tail of the dog.
Track Bars, also called Pan Hard bars,, These positively LOCK the body in position (side to side) over the axle,,, NOTE: this is why independent front suspension was such a big thing when it came out on pick ups back in th 60s. IFS does not need a FRONT track bar, as the two half axles each run to the body and thus lock it nicely.. Likewise a car with STRUT suspension already has one.
But on a motor home most folks say the rear is where you need to put one first, I put it on the front,,,,, BIG DIFFERENCE.. I will do the rear later
Ultra Power track bar is my first choice if it fits your chassis.
(Well built, low cost).
Finally steering stabilizers,, These devices try to keep you pointed straight ahead,, The two I suggest are the Blue Ox Tru-Center and the Safe-t-steer with the adjustable center option. Both of these are easy to adjust if they need adjustment.. VERY EASY.
How big a difference do they make?
Ever see a movie or tv show where a novice piolt has to land the airplane.. They warn him but when he disengages the auto pilot to take manual control he still almost looses control.... THAT is how much difference it makes.