Small hotshots

You'd be under 10,000# with a 3/4 ton pickup, so no log book and no medical card UNLESS you haul haz-mat. As soon as you hook a trailer to the back, you will exceed 10,000# GCWR and therefore will have to start keeping a log book and pass a DOT physical. If you upgrade to a gooseneck and that pushes your GCWR above 26,000#, then you'd need a class A CDL. If the state doesn't already require vehicle inspections, you'll also have to have that done. Maybe not under 10,000#, but for sure once get up over that...inspections on both the truck and trailer.

In any case, though, you'll need usdot and mc numbers, either your own or leasing onto a company. You'll also need the liability & cargo insurance as required by the regulations. Once you start pulling a trailer, you'll also likely need to register with ifta...although that may be required from the start with just the pickup, so consult the state about that to see what the exact requirements might be.

I'm sure others will chime in with more, but that's a start. This isn't really something you can wake up one day and say "hey, I think I'll do this today" and get to work.