Radio on Until Door Open, Power and Ground?

Can I get the +12 and the ground from the radio harness? Or do I need a dedicated line run?

You can pull it from the harness

The pink wire is what you get as switched power going to the radio and what you feed into the radio to make it think the accessory line is still there.

I did the install tonight it took much longer than I expected, but I was working in a small hole in the dash and I ended up using cable ties to secure the relays on the radio as there as no other place to put them.  All my wires are 18 gauge and the stock wiring is much smaller for everything except the constant power for the radio it looks like 18 gauge.  So I should be fine on all my wiring.  The click of the relay when I open and close the door is going to take some getting used to.  Also did it all in butt connectors since my attempts at soldering a few test pieces of wire didn't work.