Arn, when I was looking for a rear kitchen TT with 2 slides, I googled "RV manufacturers", got a list and went to their websites. I looked at floorplans until I found the one I wanted. Didn't take that much time.
Our old trailer had the crank-up/rotate antenna. Our new trailer has the omnidirectional. Don't really notice a difference, except I don't have to rotate the antenna to get different stations and never have to worry about whether i cranked it down when leaving.
If I really want great reception, I'll go with a satellite dish. Otherwise, my DVD player works just great.
IMHO safety chains are window dressing. Most towers don't have them adjusted properly (too long, not crossed over), and if the trailer ever comes off the hitch (should never happen if the latch is locked properly) there's going to be a horrendous crash whether there are safety chains or not. Most safety chains are attached to the bottom of the tongue by a little lag screw that would probably break if the chains jerked on it.
You could buy this;
I have also seen "This site occupied by a Class A, we will be back",
don't know where they got it.
When I left, I would take a picture of the sign on your cell phone to prove it was up there.