1992 Jeep Comanche - have you ever seen a bench seat bolted into the back What safety precautions would you need to follow?

All seats and seat belts must be tied into the frame. Make sure you bolt directly into the frame, and i would suggest using lock washers or some blue loctite to make sure the nuts don't back off.

An additional safety precaution would be to add a roll bar (also frame tied) over the top of the seat you are installing...just in case.

You may also want to check with your local and state laws...many times these differ on a subject like this.