Our 2006 View came with Michelins . . . replaced them once with Michelins . . . no problems.
Our current Navion came with Continentals . . . they are noisy, I don't like them, but not having any wandering problems with them (although the newer style V6 chassis is more stable than the previous I-5 one).
How much pressure are you running in your tires? Follow the sticker recommendation by the driver door. Should be running somewhere in the range of 60-65 PSI.
Does your Navion have air bags on the rear? If so, be sure they are aired up properly. If not, you might want to get some (our View came new without air bags, I installed Firestone Ride-Rites and it made a big difference, I kept them at 70 PSI).
Warren and Debbie
2014 Tiffin Allegro Breeze 32BR