350k miles! My baby!

Ive posted here on another thread but got no help.
I will do anything to keep this jeep forever. Its been purfect for the 13 years I had it. My dad got it brand new in 1998, then I purchased it from him in 2007 with 245k miles, now 346k. We both had ABSOLUTELY no problems with this jeep. We both took very good care. We always used mobile 1 senthetic . This engine and transmission are incredible. Does not burn not one drop of oil. Tranny shifts extremely smooth, never problems. Was garaged kept untill 2015 when I had to park it for 18 months at my moms. I was away and when I returned to get it back on road, she had it parked in grass next to a creek.
needless to say. Now i have rust problems.
Very unfortunate Since she had unused garage, i was so upset.

Anyways. Ive been posting on forums like this and I dont understand why Im not really getting responses. Only One fellow on another very popular jeep forum knew exactly what to fix. But I havnt spoke to him in a while and im so close to finding the main issue... all I know is its something i gotta do myself. I have no choice. Most garages I went to do not wanto work on it. And the ones that would have no clue.
. Ill try to make this long story as short as possible and to the point.
ok, one night I pulled my light switch **** to turn on my lights and the entire **** completely pulled out and there was like a nice size spark. Ok no headlights, called AAA.
next day, i got new light switch from auto zone. Installed it but It wouldnt work right, i can only get my parking lights on. Figuring switch was faulty, i took it back , got another , did same thing. BUT this time I forgot to unllug battery and I ended blowing the headlamp fuse, the one inside hood. Ok ..once I replaced that and got my lights working and switch working..
Thats when very strange things began to happen...
Once I replaced fuse I blown...My engine light is now on...and no reverse lights and my jeep refuses to shift into OD.
ok...i did research...Found out it could be NSS because reverse lights are out. Ok so b4 i decide to get a new NSS, i wanna clean it and beable to get code to find out exactly whats wrong. Cleaned it, it looked perfectly fine so i put it back on.
i go to autozone to get it hooked up to code reader thing . And it cant communicate. I even tried getting code manually by holding in OD and turning key on..no errors.
so the fellow on this other forum told me that that port where the code reader plugs into, gets its power from........THE LIGHT SWITCH. Ahhh.

Getting somewhere now. So i tested the port, and found out theres no voltage. So. I get a jumper wire, splice a corner of power wire from light switch and jump it to the port. Now it shows it has power now..! So im like YAY! I CAN GO BACK to autozone and finally get a darn code. Well..even though i got power to it...still cant communicate..BUT im happy to report My OveRdrive works now... but ONLY when MY jumper wire connected its .. and when it is. All.my dashboard gauges stop working...
Still no reverse lights.
ok..wtf
i just found out today that if i start jeep before connecting my jumper wire, my dash actually will work but only my gas,oil,temp, battery gauges. Not tank/ speedometer.
so I almost have this fixed. Was so worried about my tranny. So me thinks that since jumping power from light switch directly to that port ( what's it called obd2?) I must be bypassing something..maybe fuse. Or. Relay?
in meantime, im not messing with it untill I find someone to give me more guidance.
I would appreciate if anyone has ideas of what I need to do or fix or buy now
Thanks
Justine