Mobile Data

I'm i the UK and I need to be able to be able to Remote Desktop into a
machine that could be anywhere in the UK at any time.

So I am considering something like the Orange ICON2 USB Modem for this
machine.

It seems to 'do' 3G when it can and the drops back to GPRS when it can't.
Assuming there is good enough reception will I be able to conect to this
remote machine via Remote Desktop?

Will it's internet connection be truly always on and accept incomming
connections?

TIA