How do I physically work with a hobby motor?
I would suggest you look at some shapelock. Shapelock.com

You can mold any type of mount you want with this. You could also buy gearboxes that are designed to mount on these hobby motors. But as cheap as they are you may want to consider buying some with the gearbox already attached. 

Most hobby supply stores have assortments of wheels, sprockets, gears and pulleys for these or you can find them on ebay.

Good luck and let us know what you build.