Got the truck smoke tested for p0171 and p0174 CEL- leaky upper intake was at fault. Installed new upper intake gasket, torqued accordingly, installed all components back into place, now the truck won't start.

Where does one start?

I've reseated the intake, inspected and retorqued the spark plugs, cleaned dust from all electrical components.

 

Define "no-start"

Does starter motor turn the engine over?

If starter motor is working and engine turns over then spark or fuel is the issue.
Pull out 1 spark plug after cranking engine and see if it is wet with fuel, if so then there is no spark, check that coil pack is hooked up.

If spark plug is not wet with fuel then there is no fuel or fuel pressure, check the EEC Fuse and FP(fuel pump) Fuse in engine fuse box.

2000 Ranger does have PATS(passive anti-theft system) if Theft Light is flashing then computer has cut off fuel supply.

Did you unhook the battery before doing the engine work?
With all the electronics on the new cars/trucks it is very important to do this now.