Severance offer, what should I ask for? - any advice?

I was offered 14 weeks of severance after 14 years as a school bus driver, and I have a few days to sign. I have read a lot of threads here and could not find my exact situation. There is a non-disparagement clause. What did you ask for?

I asked for two more weeks and a neutral reference. They agreed to the reference and added a week.

Ask for the offer in writing and do not sign on the spot. A day or two to think is normal.