Thanks for all the comments, it does feel good to have it running again. A few small (hopefully) issues to work out. Now that the truck is so quiet with the exhaust hooked up, I've detected a regular miss in one of the cylinders. Don't know which one yet or why, going to the garage after I type this to start trouble shooting. It doesn't get picked up by the PCM and throws no codes, but it's definitely there...........
Another isssue and it's probably of my doing is when I shift in or out of P or N all my gauges dip briefly to 0, the voltage goes from 14 to 12 and the lights dim if I have them on... I suspect I crossed some wires when connecting the P/N switch on the trans.....
Last issue is that my starter now stays engaged too long after the engine starts, this symptom is new, unless I couldn't hear it before with the open exhaust. Sounds like a stuck bendix... it releases about 3 seconds after engine start.

After I figure this stuff out, I'll install sound deadener and carpet, reinstall the interior and start driving this thing regularly....