I too replaced my trailing arms, with very good results.
Your TV/Radio swap is a bit difficult to address without being there, but there are some basics.
I assume you re removing the old 80lb RCA and installing a flat screen in the same place. If your coach has the "center TV over the dash" typical of Monaco, it's like mine. After hitting our heads on the TV cabinet many times, and deciding we'd like a clear view when parked in scenic locations, we decided to raise the bottom of the the TV cabinet to match the side cabinets, and move the TV elsewhere. I know this does not address your questions, but it's something to consider before anything else.
If you plan to keep the TV there:
1. The old TV is HEAVY - you need two strong people to control it during removal.
2. The hookups on the new TV with be similar to the hookups on the old TV, PLUS there will probably be additional hookups available on the new one.
3. Before you remove the old TV, prepare some sort of labeling system for the cables you unhook. They may already be labeled. If not, label tham BEFORE you unhook them. Hook these cables into the matching inputs, and outputs, just like on the old TV.
It sounds like you want to add some things, and your new TV will be set up to make those additions. Your new owner's manual will show where to hook them up.
You can get alot done yourself, but to do it all right you need either a media-savvy teenager or a professional to show you how to complete the hookups and make the right settings from your new TV menu screen.