Sorry to hear you're having reliability problems, Paula. I thought the Lexington line was very well built.
Seat belts are a real installation nightmare, as the Federal regs can't easily be met by aftermarket installations. That said, it's my opinion that any belt system is better than none at all.
In our rig, we have lap-only belts for pilot and co-pilot, a lap-only belt for an occupant in a barrel chair immediately aft of the co-pilot and three lap belts on the jacknife sofa aft of the pilot's seat.
The barrel chair belt is tied to the seat base, as are the two front seats. The sofa belts are tied to a major tubular structure under the sofa. Frankly, I'm not convinced that tying the belts to the seat strructure is valid. I don't think the fore/aft adjustment rails on the two front seats are strong enough. After many years with three-point inertial reel belts, we feel a bit vulnerable with just the lap belts.
Anything is better than nothing, so as long as what we've got doesn't introduce additional hazards, I'll live with it.
When our kids were young (2 through 8) we had a big Mercury Colony Park wagon. When we bought it it was the latest state-of-the-art. The driver and front passenger had the most Mickey-Mouse set of belts you can imagine. No inertial reels and you had to individually adjust the straps every time and plug the shoulder belt into the lap-belt buckle. Since I'm 5' 10" and DW is 4' 10", it was a real PITA.
When we went on trips with the kids, we used to stow all the seats aft of the front bench in the floor and the 4 kids had free run of the back. We just used to put sleeping bags and pillows down, and a bunch of toys for them to play with.
They all survived to adulthood. The only injury ever experienced was when our youngest fell out of the car when he was the last to board. He landed on his head in a restuarant parking lot. A brief ER visit showed no lasting effect. He now lives in Tokyo with his Japanese wife and ia a Microsoft Certified Support Engineer, so I figure tha incident wasn't a long-term problem. None of the other kids suffered any injuries in all the time we had that Mercury. We travelled Seattle to Tidewater VA and back and had trips from Tidewater to Disney World and to friends in Rhode Island.
Of course, our kids are all paranoid about their kids getting hurt and they have all the belts and chairs, etc. It must be very boring for their kids on a long road trip, to be strapped in all the time. The grandkids are reaching adulthood now. It will be interesting to see how they treat their kids!
Frank and Eileen
No longer RVers or FR owners