In the summer, its a breeze getting them in and out of the back. In the winter not so much.
To get the dealer to install the tethers, the vehicle has to be 10 years old or newer. I can give you a part number for the tether for the 97/98. It just bolts to a "foot" on the bottom of the seat. For 99 and newer they have a reinforced floor area where the tether mounts too.
You will likely find that the rear facing baby seat will need to go behind the passenger seat in order to give it enough room. The front seat is not supposed to touch the car seat for it to work properly. Once they are forward facing, they are find. Plenty of room. They might kick your seats though.
They are not practical, but I won't get rid of my Jeep.