What is the best 12 volt impact wrench to take on a road trip and who carries them?

im awfully partial to dewalt stuff. good quality but a bit spendy

Dewalt is good has good toque and well made my first choice usually for corded tools- Makita is my choice of cordless tool = in quality to DeWalt but has a better battery and fast charger!

Milwake is good
Hitachi is good

Bosh so-so Good quality DIY
Black Decker fine for DIY

It's likely that the tool can swap out the size of impact sockets; just like any 1/2" drive tool.

Chances are either place has much the same high quality made in China products