I wouldn't consider trading it, they're good machines, and once you fix this charging issue you are good to go for a very long time. Alternator failure on these is rare, and once corrected should give you many hours of trouble free service. I would look into getting the hour meter working so you can do periodic maintenance as scheduled.
Here's something else to consider: the dash cluster could have a short that caused a problem with the alternator, so once the alternator is fixed and you're getting the correct readings at the battery showing the charging system is working, if the dash battery light is still on the dash cluster may need replacing. I doubt it's a problem , but better to know to look for it in case.