All you have to remember is that people ship snakes all the time across vast distances. Just treat them the same way as if they'd be shipped, only you don't have to worry about what container, as it's going with you. So a sterilite tub or sturdy box are fine, although a shipping box would work fine too(especially because it'd be insulated).

Driving with them, you don't have to worry about them being tossed about by a indifferent shipper! They should be prefectly comfy for the ride. Just make sure the ending place's cage is warmed up properly when you're ready to place them in the new home. Some temp fluctuations could happen, so you wanna be safe!

Make sure and check on the laws too, I think SF outlawed a lot of snakes.