I can't exactly help with the fuse box wiring. I happened to be installing a CD changer at the same time so the dash was opened. I tapped into the stereo pwr source. Alot of people have been using the tow package wiring to tap into. I just threw these out there as other options.
You mention the vent in the back of the cab for wire routing. Prior posts on this board said you can get alot of dust and dirt coming thru there with it opened from the cable. There is grommet under the cab you can use, just slice an opening. I ran mine thru the third door, behind the molding, down to the door sill,up to the dash and under the heater vent. I have a red truck so I covered the black cable with red heat shrink.
The Uniden I have is pretty compact. I mounted it with the one screw holding the lower part of my grey dash and the black heater vent cover together. I needed to drill a hole in the center of the cb mtg bracket and bend it a little to get it to work. Also, I cut a thin strip of rubber the same size as the bracket and placed it between the bracket and the dash to eliminate scratching of the dash and rotation, since only one screw is holding the cb in place.
My antenna is a magnet mount on the roof. Yes it make me about 12 ft tall. I do hit some tree limbs and low overpasses now and then.
As far as distances talking to others varies.
A mile or so is said to be good with a basic set-up. A CB shop can work some magic inside the CB to boost its power, but it's not really legal. There are more expensive options too. All CB's really have the same power capabilities out of the box. It's the gadgets on them that changes prices between models.
This place has very good prices:
This is getting lengthy any more question just ask.
PS- Tina, off topic real quick. I've read most of your posts on the rear window leak. Did you ever try filling the crack with super glue or the like. I can't remember if you did. And I just can't go back and read the hundreds of posts on the subject.
1998 F-150 XLT 4X4 Supercab Flareside
Bright Red, Med Graphite 60/40 Int
4.6L V8, Auto, 3.55 gears, HD/Tow Pkg, ORP
Slider, Keyless Entry/Alarm, Pwr/W/L/M/S
Uniden PRO520XL/Wilson 1000 CB
Alpine CHM-S655RF 6 CD Changer
Ventshade Stepshields in grey color