1) I'd be careful cleaning it up too much. Personally, I would get it serviced just enough to get it working reliably, and leave the rest of the grime and wear on it. Those are beautiful cameras with tons of history, and I would hate to see something like that get polished back to perfection erasing that legacy.

2) They don't have light meters, but you can either learn Sunny 16 which can be fairly reliable when dealing with outdoor natural lighting, or get any number of phone apps that will do metering for you.

If you do go the phone-metering option, I'd try to test the metering provided by your cell phone camera by taking digital photos (or a test roll) using the suggested exposure to be sure that it's accurate. I believe on iPhones it's pretty consistently good, but I found that on my old HTC phone, the metering apps weren't very accurate. You can also get an actual light meter attachment for your phone to improve accuracy.

3) Get a classy old school meter like a Lunasix