i recently added Sirius to my TT. I have a 27BH wildwood LE and was not wired with Satellite radio.
Here is what I did.
1. Buy an extra "car kit" for your sirius/XM radio. Sometimes you can just buy the pieces you need on ebay as seperate pcs.
2.Remove current radio/cd player. (The radio is running off of 12V DC).
3. Splice the Sirius Car 12v plug into the Radio power line. (Cut off the part that you plug into the car)
4. While the radio is removed, Drill a hole thru the ceiling in the cabinet where the radio sits to the roof.
5. Run a cable snake up thru the hole it is exposed thru the roof. Use duct tape and attach Car antenna plug to the cable snake.
6. pull snake thru.
7. Replace radio and leave access to the 2 cables you need for the Satellite radio.
Note: you might want to purchase an RF bypass kit. Traditionally, any Sirius radio needs two antenna based signals. first is the satellite link and the second is the a view of the Radio antenna. (standard FM) In a car, most of the time, your satellite radio has a clear shot to the FM antenna. In a camper, it is often blocked. Therefore, you can by a bypass kit that basically attaches to the camper FM antenna and then plugs into the TT FM radio jack - where you removed the FM antenna in the first place.) I foound this dramatically improves signal quality.
On a side note, another mod that I made is that my camper doesn't have outdoor speakers. There is a A-B switch. For my camper, the "A" is for front bedroom and "B" is for the rest of the unit.
I detached all of the speaker wires and spliced them together so all run on Ch A.
While the radio was removed I added two weatherproof speakers (goto West Marine) to the outside of my TT and attached them to Ch B.
hope this helps...
2004 Wildwood LE 27B
2004 Suburban Z71 4x4,5.3L, 3.73. Reese dual cam w/WD