1975 Dodge Dart Sport 360 will not crank from key

NSS (Neutral Safety Switch) for the no start. It's mounted on the transmission which has to be in Neutral or Park to ground the starter relay; sometimes the linkage just needs to be adjusted; try wiggling the shift-lever in Neutral.

As for the lights well, you'll have start at the bulbs, and make sure the chassis is grounded back to the battery. There is a ground on the core-support on the driver's side behind the headlight. Another from the firewall to the back end of the passenger head. And another one at the battery. And of course the one on the column. I think another one behind the driver's kickpanel, and one more in the trunk near the lock.

If the signal/running light bulbs are all the correct type and working, but the rears will not work, that usually points to a bad signal switch. But if they do come on but don't flash, that points to a flasher. There is a separate flasher for the hazard lights.