Like Weave said, it will vary with the company you're leased to. The smaller company we're leased to will offer us loads up to maximum, which for our "C" is just shy of 10,000 lbs and/or 8 standard skids flat. The majority of the loads are smaller, though. We have only lost a few that were too big or too heavy..
The bigger companies FedEx will pidgeon hole trucks by size, a "C" is 14 feet and 5,000 lbs and anything heaver goes to a "D" or "E", but they WILL offer you lots of "A" and "B" freight.
We park in the back yard and the neighbors look the other way, we're lucky to have a back alley for access.
Yes, you do have to hit the chicken coops (scales) in every state we know of. As for license, here in Michigan you can either have a GVW plate or an IRP. We plated IRP, 'cause that got us out of paying sales tax. We have an IFTA permit and have to file fuel tax quarterly.