Being a Tech Geek, I have been adding stuff to Suzy Q. Radios have been the latest and the darn radio antenna have always been a problem. I hate having a bunch of masts sticking off the mirrors, only to be smacked while trying to get around the trees while boon-docking. So, I adjusted things a little.
My XM radio mast is sticking up behind the cab. Suzy Q used to carry a sattelite system when she worked for a living. I used the same hole, ran the cable along the inside panels, over the driver door, down the post and through the console to the XM module. The support bars for the side fairing fit the mounting hardware from the antenna maker. The black mast is now the highest point by about 8 inches. No problems with trees brushing past and knocking the mast off. The signal is great.
A Garmin GPS antenna was added to increase the power for the Street Pilot III system. I don't like drilling into the roof or running cables to an exposed view. So, the external antenna was put into a pocket that is in the front and top right hand corner of the cab. It is behind the headliner (remove the privacy screen track to see it), directly above and to the right of the upper storage bins. A little velcro, some twisting and a couple of knuckle scratches later, the external box was attached to the inside of the roof. The signal strength went from mid-point on 4 or 5 signals to near 100 on half the 9 or 10 sats. Great improvement and the antenna is not visible from the outside!
One other thing about the Garmin SP III: dash mounts (not the bean bag mount). Suzy Q has shaken 2 of them apart, the mounts are not very strong. I ended up getting a different mount (RAM) that raises the unit off the dash. Stronger and better looking.