As an over the road trucker, I can tell you that there is very little activity on CB. I can go days without having the squelch break, and when it does, it's usually a couple of bull haulers running convoy, or shops advertising (generally truck washes and chrome shops, but Nevada is interesting...).
I do plan on putting an HF rig on my bike. I'm not sure what I'll use for an antenna; I may dust off my old Outbacker.
73 es CUL deN3EOP/5