A bit late now, but I will leave this here for future reference, unless you would like it removed.
There is an art to sound damping. The "cover every inch of your floor with Dynamat" only serves to empty your wallet and add weight. Changing the resonant frequency of each panel is the goal, along with eliminating harmonics. A "piece" of sound damping (not dampening) material in the center of a panel may be all that is required. Several types of sound absorbing material may be required in order to achieve the desired result. I do not doubt that you have seen some improvements, but you likely cost yourself a bit of time and money unnecessarily.
On the CB antenna, a metal one is preferred over a fiberglass one. If you are in the woods, the antenna should be spring mounted, the fiberglass ones will break at the base if hit hard with tree branches. The antenna should also be "tuned" for your vehicle, especially cabovers, as they are a bit weird. This provides optimum range and performance and can really make a noticeable difference.
Looking forward to seeing the upcoming cross country adventure.
Cheers