The vehicle is not noisy or uncomfortable to me. If the wind isn't blowing, I'm on uncrowded roads with sufficient lane width, and I keep the speed at easy pace, I can drive the motorhome as far as any vehicle without fatigue.
I think you're going to have to drive it first and see if there are any factors you want to change. In my case trying to tighten up the handling was my effort to reduce fatigue.
If I were in your shoes, two tips:
1. Get wheel alignment. Research Harvard's posts on caster and ask that it be set that way.
2. Weigh the rig and set tire pressure accordingly.
From there on any changes or ideas should be based on your needs.