***Update***
The Good
Been driving her 10-20 miles per day this week. The mild tune up (plugs, wires, cap, rotor) along with the heated o2 sensor conversion, shorty headers, OR Y-pipe and exhaust has made a noticeable difference in power. Engine seems to be mostly happy, idle drops quickly on cold starts and has enough power to keep the trans from shifting as much. New oil pressure sensor fixed the oil gauge.
The Bad
Once in a while the check engine light will come on. Seems to happen after about 30 minutes of run time ever other day. There is no noticeable changes in performance before or after this happens. It did this prior to the tune up but thought it was from the bad old pressure sensor. No codes yet but haven't had the light stay on long enough to hook up the code reader.
Popped a brake line, the leak was right next to the driver side Y-pipe flange so may have nicked that when I was installing the exhaust. Brakes still work, but pedal goes to the floor so need to to fix that asap.
Interior needs to be put back together, seat belts tightened, speakers hooked up, rear window latch, sound/heat insulation. Horn doesn't work, shifter is loose and is hot inside the cab. (Might have to un-delete the AC LOL) Passenger floor still leaks sometimes (after sealing cowl screw) Speedo went out this morning. Left Blinker is flashing faster than right...Blinker fluid level was good so prob just a bad or rat chewed wire somewhere. Both sides marker lights, license tag and passenger brake lights are out. Looking into LEDs for those. Pulsating/clicking sound from inside the cab, think it might be fuel lines or something making contact with the firewall/trans tunnel. Didn't feel anything in there when i was installing the exhaust but will re check that when replace the brake line.
Transfer case shifts to 4hi fine now, but not to 4lo. Doesn't bother me that much right now but prob is sign that it needs rebuilt.
The 700R4 is still a little upset. Reverse slips under the lightest amount of throttle, especially on an incline. Shifts delayed under 3/4 or more throttle and overdrive still lugs. Usually keep it out of overdrive on back roads. Trans fluid still reddish but hear horror stories that replacing could kill it sooner... In another thread this kit was suggested but never worked on a trans before so guess I'll pop my cherry on that eventually...
https://www.ebay.com/itm/324170377137
Suspension and steering are awful. Front bounces like a pogo stick, steering has lots of play and wanders. CV boots are ripped. Truck feels/sounds like cinder blocks being thrown in the back over small bumps and potholes. Body mounts are toast. Ordered 4 new shocks so just starting with that.
Fuel leaks if tank is filled up more the half way, assuming I will need to replace the fuel filler neck. Do smell fuel occasionally.
Header & Exhaust bolts need checked/re-torqued, exhaust piping secured better...(muffler is restingon/making contact with a cross member)
Paint and Body - Replace rear bumper, new fenders, inner/outer rockers, cab corners. Weather striping, washer fluid nozzle, Sand/Paint roof of cab & hood...unless i can find a non rusted/acorn dented used one.
Conclusion
There's still tons to do & lots to learn!