How do I determine the value of this Unique property??

[Steven M.]

A customer of mine mentioned she is selling off all of her properties as she is 80 and looking to enjoy the rest of her life task free. 

My wife and I are going  to look at one of those properties this week but don't know exactly how we should calculate the properties value as its unique to the area so there are no comps. My customer also has no idea what the value of said property is worth in todays market.

The property consists of approximately one acre of land located in Maine. It includes a 3-bedroom, 1-bathroom ranch house along with a private street hosting a small mobile home park with 5 units. From what I have been told, these Mobile homes are grandfathered in as they no longer allow these in this area. ( I have researched further and found that these mobile homes can all be replaced at anytime with ones of the same dimensions). 

I'm hoping for some guidance and any suggestions/ help is greatly appreciated.

The specifics of the property are as follows:
Land: 1 acre 

Income Generating Units: (built around 1995 all in good shape)

Ranch House: Rental income of $1,200/month

Mobile Home 1: Maintenance personnel reside here rent-free (not generating rental income)

Mobile Home 2: Rental income of $980/month

Mobile Home 3: Rental income of $1,000/month

Mobile Home 4: Rental income of $1,200/month

Mobile Home 5: Rental income of $1,200/month

Financial Information:

Estimated Annual Taxes: Approximately $2,500