Need advice on occasional use car seat for 4.5 yr. old

[lhaedge]

For my 4.5 yr. old we have a Regent and for my 22 month old we have a Marathon in my car and we love these car seats. But, they are both big car seats and I have a hard time installing the Regent because we can't use latch anymore, so we rarely move the car seats. But, I have an older daughter and two older sons, who could possibly help us out with the kids at times, if there is a car seat option for their cars. Also, we were out of town recently without our car and considered taking a taxi, but didn't have car seats that we could travel with. So, I've been trying to find the safest car seats for the kids to use occasionally in situations like these. I've been researching the Safeguard Go and the RideSafer Travel Vest and Parkway for the 4.5 yr. old. I would love to hear any advice you may have regarding these car seats or suggestions for something else I might not know about. I have a Roundabout that is 5 years old that my 22 month old daughter can use, but how old is too old for a car seat? She weighs 26 pounds and is 31.5 inches. My 4.5 yr. old son weighs 49 pounds and is 43 inches tall. I am hoping to find a car seat that isn't too big, because my kids vehicles are very small and only have two doors. If we ever do any carpooling, it would also be great to have a smaller car seat for that.
Thanks,
Linda

[momtoB]

Britax seats expire 6yrs from date of mfgr. There s/b a sticker on the side of the seat that gives DOM. If it's 5 then you've got less than a year left on it.

For your 4yr old - what is his torso height? How many inches is he sitting, bum to top of shoulder? Which harness slots on the Regent is he using currently? How much does he weigh?

The Ride Safer vest is safe, and safer than a booster, however it offers NO side impact protection. If he can use it riding in the middle seating position then that would be ideal. If there's only a lap belt there it REQUIRES a top tether.

hth