Well I've been at it again. I like to build stuff so I just got done building a rear facing seat for my Uforce 500. This is similar to a rear facing golf cart seat.
I used 14 gauge 1" square steel tubing for the step and footrest frame. This frame fits where the tailgate is attached, and is anchored by a a single 5/8" bolt through the hitch ball hole. The heavy 14 Gauge tubing is overkill, but I had it on hand.
The seats and back rest are marine grade vinyl (once we got the vinyl from Amazon we understood why it was so cheap as it was seconds and had manufacturing flaws) over 3" medium density upholstery foam, attached to a 3/4" plywood base. The seat and back rest supports are made with 1/4" x 2" flat hot rolled bar and attached to the floor by removing two box hold down shoulder bolts (one on each side) and replacing with longer hex head bolts, flat and lock washers.
The unit is made in two pieces with just three bolts needed to attach it securely. Takes just a couple minutes to mount everything after removing tail gate. I still have to make a safety apparatus to keep the bed from accidentally being dumped while the seat is in use. I have seat belts ordered. I fabricated a safety bar out of Schedule 40 1" PVC tubing. This give a little more safety and peace of mind for the passengers, like riding a ferris wheel. I plan on hinging the back rest in order for it to fold over the seat allowing more access to the tool box.
We live where there are practly no hills and our riding is mostly wooded trails and fairly flat sand dunes, so this give us the chance to take a couple passengers along. It is pretty comfortable to ride in.
My wife did all the cushion work and tells me this is the last job she is sewing as it it getting too tough for her to do decent work. I agree that its too hard for us old dudes. At nearly 78 years old, we do not have the skills we once had. Anyway, I enjoyed doing this build. Total cost was about $75.00.