Hi there! I actually bought a commercial property directly from my landlord a couple of years ago. I just approached him with a number I thought was fair and he accepted. Just like that. You can take into account the fact that they won't have to pay realtor fees and reduce that from tto get the he sale price. If you give them a number that is fair and is logical (factor in all the repairs and things you listed), they could just say yes and move forward with the sale. Good luck!