All these stories sound oh to familiar. But I did make it. My first 2 510's were undrivable,so they were towed.
3rd one was bought off of ebay for 6500. Bought it in San Diego, guy said it could be driven, so I drove it home to Atlanta, GA. Only a few hiccups on the way. Definitely a small set of tools should of been the first stop before hitting the road would of saved a ton of grief. First the dang throttle cable popped off at a gas station. I needed a set of allens to fix that. Next I had shoddy wiring for headlights, they would come on when they want. I had do the jiggle if they turned off at night. only other thing was I hit a nail and got a flat in louisiana. Not to bad for a datsun. After fixing all the little issues. I ended up dailying it a whole year in Atlanta putting close to 25k on the motor, 40 miles one way.
Next one I bought was a 620, guy said it would drive home. I get about 10 miles down the road and the dang thing starts smoking. Tranny died 2 miles later. It was bone dry 5 speed. Had to get it towed. I guess we've all been there. Datsun's can be reliable but just like any old car. They need maintenance probably more than 90's daily drivers.