so are we trying to move ourselves, or stuff?

I will stick with the Bike as the best self mover- at least if leaving from home.

20.00 for a used mountain bike at goodwill- cheap, available parts, tough, mobile, and fast. Even if you are out of shape, as long as there is flat ground, you will move farther.

But....

I am at home 10 hours of a 24 hour day. I don't have room in my 12 yr old Subaru Forrester for a bike, even a folding one....

I have not settled on a model for my car, but I have experimented with a kick/razor scooter. My kids have several folding models that weigh under a pound. Even without practice I still went 5 MPH for about 1/2 a mile, and was not out of breath. I know I can do it with a small backpack.

I am intrigued by this site- http://www.cambiecycles.com/scooters.html adult sized scooters- under 200.00 Not sure if would fit in a car.

I think I would argue that moving people faster is in "most" cases going to take precedence over more stuff slower. Me plus bike plus 30 pound pack= 10+ MPH. that gets me from Omaha to Minneapolis in 4-5 days, assuming 8 hours travel. I am 43, and in average condition. Your solar powered scooter will pass me on day 1, but unless you can find a way to recharge, I will get there first. I suspect that the bike pulling the stroller would be harder, but still, the mechanical advantage is hard to overstate...

I am willing to be wrong- maybe your bug-out is only 5 miles away, and not stocked;