Hi Rich and welcome to the forum!
Ain't it great to have so many friends help spend our money?
A couple of thoughts come to mind:
*Driving ever faster shouldn't be an objective but we all want to feel comfortable while driving.
*IMHO, you shouldn't have to go to a 42 TAG to have your coach handle well. Yes, from what I understand, tags handle much better at highway speeds but there are LOTS of things that can be done to improve handling on an ill mannered rig. You say that the front end feels light due to all the weight being in the back. Have you gotten it weighed? This type of "road wander" is pretty common. Being in NJ, you are about as far away from the best shop I know of for this type of thing... Henderson's Line Up in Grant's Pass Oregon. When my coach had only 6000 miles on it I had them assess the performance and then add a Safe T Plus steering stabilizer, motion control units, a new Safe T Steer bell crank, and adjust the steering gear. Driving my coach went from being a two hands on the wheel/white knuckle experience to being nearly hands free. Best $2200 I ever spent.
Best of luck to you whichever way you go.