When my kids were small (under 20 pounds), they rode in a "bucket" type carrier that was part of a stroller set. It was held in place with a lap belt and always faced backwards.

When they got bigger, they got proper car seats that faced backwards, that were also held in place with just a lap belt.

Now that they are over 30 pounds, the car seats face forward. Our car has the third anchor points that you need for a forward facing seat but the Runner doesn't so, if both kids are in the truck I use the front cargo tie-down loops to hook up the seat straps. If I have only one of them, I put them in the middle of the back seat and run a tie-down between the two front tie-down loops and connect the seat to it. The loops will pull out of the floor before the strap tie-down breaks.

BTW, the kids (2 and 3) love riding in the truck since they can see out. The windows on the car (A4 wagon) are too high for them to see over. Especially good in the summer with the roof off.

Sean