Different State Requirements for CDL?

In considering the size trailer we will get to tow our two FE's we are wondering what is the truck/trailer weight combination that we need to stay under to avoid needing a CDL and to avoid needing to stop at weigh stations. We will be towing with a Ford F350 dually.



Would anyone have this information? Is it different based on what state we are driving in or is a the same everywhere in the US?



Thanks!

Chet