First park questions

We are in the due diligence period of purchasing our first park. We went out to look at it and there are several things that we and the home owners need to clean up. My question is…what can we “make” them (the home owners) fix? Paint homes, fix broken windows, junk in their yard that also spills over onto empty lots? What is the best way to go about accomplishing this? Also, there is one home that used to be there, but it looks like it’s being demolished by hand. What should we go back to the seller with…money off agreed price, or he has to remove entirely before closing? Thanks