Look at the photos that shows a tape measure by every dimension. That should answer your questions.
This was used to haul two bicycles. Those other two parts you slide on the horizontal piece if you want to haul three or four bicycles.
2 inch hitch rack makes this heavy duty compared to the one and a half inch versions.
It does not swing down but has a bolt in the hole for that so you could possibly rig up a quick release hitch pin to make it swing down so your tailgate could go up.
I have a van and don’t need a hitch rack.
-if interested use the craigslist email, and I will get back to you.