I installed two SO239 antenna mounts in the bed of the truck just behind the cab. Originally I wanted to use lip mounts on the side rails about a foot back, but I couldn't get those to tighten securely. So I opted to take the lip mount bracket off the antenna mount and use two of the bed tie down rings to mount them. (see attached)
The left antenna is a Comet HP-32, the right one (not pictured) is temporary. Eventually the twin mounted antennas (for my twin) behind the cab will both be the same model/look for VHF/UHF. I'll most likely replace them with black 5/8wave Comet or Diamond. Depends on how high they are since I park in a deck at work. The HP-32 barely taps the hanging sign as I enter the deck. I used a short NMO mount antenna in the center of the roof on my old Ranger and it would scrape the main beams by about 2".
If I put a camper shell on the back, I can simply unscrew the antennas and connect the shell mounted antennas to the SO239 mounts. If I install a tonneau cover, then I'll have to do something different. Either way, I plan to purchase a Little Tarheel and mount it just forward of the bumper on the side by the left tail light.
In the attached photos, I still need to tiewrap the coax loop out of the way.
I'll try and follow up soon with photos on how I mounted the FT-857 and FT8800 control heads on the dash/console without any holes or drilling. Two radios installed, no holes for anything.

The coax runs into the cab under the rear passenger seat through the plastic plug. The radio bodies for now are laying under the back seat on the driver's side. I'll also follow up with how I did the power.
Tom