s N s wrote:
Ours too is bone stock and I have no problem with any wander. I keep our tires inflated to 95 all around but that may be different for everyone as far as weight goes. Also as mentioned be sure not to overload the rear and take to much weight off the front axle within reason. Another trick if you're are new to driving a motor home is to look further down the road rather than looking down right in front of you. It for some reason gives you a better perception of keeping the rig straight and narrow down the road. Good luck and hope the issue get's resolved.
Along with this, make smaller corrections and expect the vehicle to take longer to react. A long wheelbase vehicle simply reacts more slowly than a shorter wheelbase vehicle, and if you're used to the latter it is very easy to overcorrect...and then have to (over-)correct again, and again, and....
Keeping your focus further down the road does help here, I suspect because you're not responding to every little blip back and forth but rather to your overall trajectory. Figuring out where the lane edges should be in relation to the dash to be in the proper position in the lane will help you keep your eyes down the road (and rely on peripheral vision to stay centered) rather than having to constantly look close up. On my motorhome, it works out that the left side of the lane needs to appear to be going straight towards or through the dashboard vent grille on the left of the steering wheel, which sure felt wrong at first even though it's demonstrably correct.