As an update to my original post,
When we use over the air antenna, all tvs work. So its not the cable inside the coach from the wall plate to the TV's.
We do get Cable TV in SOME campgrounds just by hooking up the cable to the outside of the rig, turning off the antenna button on the wall plate, and doing an AUTO search under CABLE on each tv. (using no cable box) So it appears the cable running from the exterior of the rig to the wall plate is fine.
But in MOST campgrounds, we hook up to the cable and get nothing. Disney Included. I would say that 2 of 10 campgrounds we get a cable signal. And we always get OTA tv on all 4 TV's. So its not coax cable problem in the RV. I just notice that everyone else gets Cable TV with no problems but I only get it occasionally according to what campground I am in. Disney advises that no cable box is needed.
I will check the TV's to see if they are QAM type TV's. I replaced one of the TV's last year with a cheap TV purchased from Walmart (less than $100). I didn't fix the problem but I frankly didn't check to see if it had a QAM tuner.