Travis
You have to be careful about TV 232 ports, many of them are "for service only", meaning you cannot control through that port. The one you linked to specifically says in the detailed specs "control/service" so you should be good.
Yes, you can get a USB-to-232 converter cable. The Prolific PL2303 chipset is common in many no-brand cables, and is compatible with Linux.
It is very unlikely that you will be able to control a TV through a USB port unless is specifically says that is an option - it is more likely they are for USB thumb drives to display pics, play music etc. If you can control through them, then theoretically I think you can get LMCE to control the TV but I'm not clear on that - perhaps a GSD? One of the other guys can advise there. I would stick to serial though... Would also be a good idea to check the already existing TV templates built into LMCE to see if yours is already there...