In Otay and San Ysidro travel trailers and other RVs are always inspected. Plain customs logic - inspect any vehicle that could potentially carry cargo not visible from the booth. They may just look into open door, or step inside and open a few cabinets. Though you'll probably be crossing farther East, Nogales-ish. The border is changing, it's not like 10 years ago. FMM, among other things - yes, for 3 days in border zone.
Don't know why 2 TV sets are needed in one travel trailer, but you better don't keep them in original packaging. They don't want to see any packaging.
