As far as I know the tc1100 is the same size as the tx2000 and should fit in the Tough Tray II. I haven't tried the suction cup mount but Marvin can comment on that as he also has a TX2000.(After a quick look, the tc1100 is actually smaller).
If you don't want to have to recharge the GPS, stick with USB. For Garmin Mobile PC, the best bet would be buying it as a package with the 20x. It will do the job just fine. I think the BU-353 is a bit better but in most cases it won't matter.
You would have to go with Bluetooth to get better than 1 Hz refresh. There are dual purpose devices such as the iTrek M7 and QStarz BT-Q890 that are both BT and USB. However their data rate on USB (115,200 bps) exceeds the range of Mobile PC which tops out at 38,400 bps. Also, there is little or no advantage in refresh rates over 1 Hz. Smoothness is only important when you are moving and watching the screen closely (or exceeding 100 mph on a regular basis).
Terry