Valuating Buildings in Park

This park I am negotiating to buy has a few park owned homes, a storage bldg, and another (shack?) that is being used for the manager’s quarters. Originally, the seller had an asking price based on the NOI, but included all the POH rent. I clarified that I was only willing to pay for capitalized lot rent. The seller’s response:

“If it’s just the spaces you want then that raises the question of wanting or valuing the storage / repair shop as well as the managers quarters. How do ya want to figure / calculate that into the offer, or would ya rather subdivide that chunk out and not get involved with it at all.”

How do I put a value, if any, on these ancillary structures? Because of the location, I don’t believe it can be subdivided.

Also, since he is willing to take less than his original asking price, he wants to retain ownership of the POH and do sale/lease backs to the tenants. I like that I wouldn’t have to deal with it and he would be responsible to me for paying the lot rent, but I don’t want one person owning all those homes. Any suggestions?