Buying or Selling a park with notes on the homes

Suppose you are selling your park and you have self financed some of the homes and the notes still have a few years left.

Lets say there is a note on a home with 2 years left @400/month including a $150 lot rent.

Would you just calculate the principal and interest only $250/mo. X 24=$6000?

What have buyers been offering for notes recently? 50%, 60%?

What have some of you seen lately?

thanks in advance