About 60% of all old tractor problems are electrical, another 39% are fuel. I would check the coil, if its been converted to 12v change the coil to 12v and save your self the resistor problems, I have never had good luck with 6v coils in 12v systems, but there are hundreds of people that have never had a problem so that's your call. Another thing is buy a new set of points, cleaning them works sometimes but never seams to last, especially for field tractors or ones that set out to the weather for long. I think you can replace points, condenser, rotor button, cap plugs and wires for $50 or so, well worth the expense. That's my advice, I don't always follow it, $70 I just rattled off is cheap for tractor maintenance if you have it but might as well be $1000 if you don't have it.
On another note, I think the Ford N's are one of the finest tractors ever made. They have there limitations and if you learn them and work with them they will preform as well or better than most modern compacts. We have 2 of them here on the farm and they get used almost daily during hay season, A finer raking tractor has never been made. We tote feed wagons around with them, bush hog pastures and field edges, dig post holes, winch firewood, grade the driveways and dirt roads, the list never ends. Parts are easy to get and cheap, a lot available at local auto parts stores, many more at local case/NH dealer, the rest on the web. They are easy to work on, I can split and change the clutch and re-assemble before coffee break, try that with a new compact. My biggest caution is if its got a loader the front end, in particular the steering components are a little weak.
Just my 2 cents.
Good luck!!!