Well, my younger son can officially fit on a trail-a-bike, so it’s time to ditch the trailer. This is an older model Dee-lite, like this one:
It does not (easily) convert from a trailer to a jogger stroller. It does, however, attach to a bike without any hardware required on the bike itself. It takes about 30 seconds to attach or remove it.
The nylon and plastic on the trailer is in excellent shape (always stored inside), tires are in good shape, and it is free of any rust. Two kids will fit, and there is a bit of storage behind the seat, too.
Made in the U.S.A., if that sort of thing is important to you.