re: bluetooth,
bluetooth uart modules are like $5 these days
I just picked one up and was talking to an arduino with an android tablet in no time.
ArduDroid: A Simple 2-Way Bluetooth-based Android Controller for Arduino
it is 3.3v (that is what the resistors are for) so you just need to level shift your alltrax accordingly (i.e. max232 or a couple resistors and a transistor, borrowed from the lower left of the
arduino serial board)
My 4g relay with its keyboard makes for a nice tiny serial terminal. If I need to tweak a controller I can just whip out my phone instead of hooking up a laptop (as well at being good at graphics).
edit, looks like an integrated bluetooth/serial "dongle" is $13, just plug it in to your alltrax and connect with your bluetooth device.
http://www.ebay.com/itm/RS232-Blueto...item1e8a0b8450