that should say "SE or some OTHER sort of cable."

I'm not sure what you would call it, but it's made by Southwire, Type use-2, 60 mils XLP insulation, 600 volts, AWG 2 Aluminum wire. It consists of 3 wires (2 hots and a neutral), all encased in rigid black sheathing. The three sheathed wires are wrapped around each other, kind of like a loose braid, and the neutral wire has 2 yellow stripes on the sheathing. The ground is a separate wire I had to buy, and I'll run it right alongside the three aluminum wires.

Does that help at all?

OK USE-2 is one of the service entry cables. You don't need to enclose it in conduit except where it needs to be protected.
If it goes somewhere where it needs to be protected from damage, then conduit (or similar) is required. As near as I can tell (going through wood joists in your post) conduit isn't required.

HOWEVER, you can not run the ground as a separate wire. You're either going to have to get cable with the appropriate number of conductors or run conduit and individual conductors.

Type USE-2 is not permitted for in-premises wiring. You need SER 4 conductor cable such as 2-2-2-4 AL, or individual THHN conductors in conduit.