Depends on where you are.
Old fashioned antennas, can work surprisingly well in otherwise non-reception areas. Or surprisingly poorly in areas you think should get great reception.
Dish or similar satellite receivers.
Recorded - add in a DVD player, if you can find one, or download streaming episodes to a laptop at home, and then watch them via a cord to the TV.
You will need to verify whether the TV needs 120v power to operate. Most do, although there are a few that run on 12v - but your trailer may need rewiring to accommodate.
More often, the sound system runs on 12v, but another thing to verify.
And same for secondary devices - DVD players, charging laptops, etc.
If that is pretty much all you want to use on 120v, if not already in the trailer, a small inverter can do the job - electronics take comparatively smaller current.
My 2 6v batteries, and the 600w inverter, can last for up to 2 1/2 days with running lights, a few hours of TV (antenna + 12v DVD), and minimal use of the water pumps, slides, and fans. Other stuff - 12v refrigerators, cpaps, can run - but then battery life can drop a lot.