Cargo Bikes

Seems like fitting the fork in there is going to take up a fair bit of space. So you’ll end up with either a standard sized cargo bike with little capacity or a bike that’s longer than usual and therefor, I’d have thought, more unwieldy.

What does a Bullit frameset cost?

Get it and report back! ;-)

I've seen them. As far as stability and strength, they don't compare to a bullitt or similar. Much smaller cargo. Not nearly as resilient. Not the sort of thing I'd want to spend real money on. Good for a hoot. Can carry one child. Wheel base ends up being quite long for all these compromises because of the head angle of the doner bike.

Breaking it down each time is cumbersome and would not really be an activity that makes you feel good.

Personally I'd go with another option. Like a surly big dummy for the kiddos with a Clydesdale fork for added utility. I like this because it's an option that can take a beating. https://www.splendidcycles.com/products/surly-big-dummy

Another option is something like the Tern bikes. They are pretty compact. https://www.splendidcycles.com/tern-gsd