I can only talk about the CB antenna and radio.
The Firestick 4" with their side mount will work great drivers side upper section of the exterior. I would make sure that the tip doesn't extend above the regular Radio Antenna on the roof so it won't get hit.
I would also add a strong spring at the bottom of the antenna.
Mounting should be back further than the pillar and possible inside the cabinet drivers side above driver.
You will have to do some removing of the stirofoam in the wall so you can get the mount bolted on and the coax connected.
Then bring the coax down the left pillar.
I was going to mount my CB on the outside wall to the left of the drivers seat.
The big issue I had was that the coax for the Firestick would reflect better if the coax is stretched out and not coiled up.
I believe you have like 18-19 ft of coax and it can not be cut and shortened.
Here is a link from awhile back on another person wanting to install a CB in the 378TS.
http://www.forestriverforums.com/for...ts-119981.html
Good luck.