64 Dart headlights, gauges, interior lights went out

I have a 64 Dodge Dart gt with slant6. I bought it after it had been sitting for about a year, started right up mostly original except for an installed stereo. I drove it around for a couple months and one day it rained and my fuel gauge stopped working. Then my Temp gauge, then my interior lights, head lights, and all my back lights.

I was also having trouble starting it until I found the ignition wiring had been burnt- so I stripped and replaced the connectors and it starts, sometimes. I'm trying to restore it although I'm not big on wiring, don't know much but I have my manuals though I haven't been able to find the problem yet. All I know is that my alternator is working fine and so is my battery. I replaced spark plugs and tubes as well but haven't touched anything else.

Any help would make my day thanks.

X2 checking body grounds & clean/inspect firewall terminal blocks too.
X2 wet headlight switch.
Please check for front windshield leaks. Spray down with water outside, and look up under dash with flashlight. Better done when inst. cluster is out of car.
If leaking, the back of inst cluster and cowl under windshield will be caroaded, remove and reseal front windshield.
(See our restoration thread, under "members restorations" titled, "ABodyBetty's new Baby comes home. It will show with pics what to look for when checking for leaks)
Then remove inst.cluster, disassemble, clean, reassemble, reinstall (also replace all bulbs with new. (See same restore thread for this too with pics!)
Check guage operations after rehab/reinstall, if bad replace guage thats bad.
Good Luck!:read2: