DonErb, welcome to iRV2.com. We are glad you have found us and join the forum. What year and make is the coach? If you will click on Go and then My Profile you can add this info to a signature and it will always be there to help us know how to help you. It sounds like there is a good possiblity that another seat can be added but usually the belts are attached to the floor. Good luck.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7