I had the fence between one of my houses and its next door neighbor blow down from hurricane Ike. I contacted the resident to coordinate payment of the fence and found out it is a rental. The owner lives in New York City. I contacted the owner and we got the fence repaired but then the owner wants some other work done to her house. I contacted my roofer to do her roof, checked out the work and she pays me and I give the money to the roofer, the same with the painter and now another fence. I realized that I have become a free property manager. That is why New Yorkers are smarter than everybody else. She has snookered me.
The next time you get a bid, mark it up 20%. That's what contractors do, and as you said, a property manager would charge a monthly fee, so for you to profit from organizing and inspecting all of this stuff would be reasonable. I'm sure that a business savvy New Yorker would not just understand, but respect your postition.