We've had an RV for almost two years, for the first year of RV trips my kids used mini's. They work but they were not ideal. They fold super small, however the seatpost is so low it can caught up on curbs and the handlebar is a little too high for both. I could use a shorter post to solve the first issue, but I was unable to solve the latter problem. For much of the past year I started using 20" wheel kids bikes with an angle adjustable stems. I remove both wheels and seatpost and pack them in the RV. They are a bit bigger than the mini's, however the kids like them much better because they actually fit on the bikes....which is the most important thing.

Honestly I think a nice kids bike is better than a nice folding bike for kids under 10.

Thanks,
Yan