finding comps for this kind of property

[Johnneice Ferguson]

I currently have a lead that I am working on. There are two properties on one lot. The main property is a 2bd, 1ba and the other house is a 1 bd 1 ba. The owner got the property from a tax sale. The owner stated that she had to purchase both the properties together. She decided not to flip it because she realized that the smaller property was not wired for electricity and did not have its own sewer or water wich was run from the main house. I'm really not sure what to look at for comps since this property has 2 houses on one lot. The arv for the main house is around $40k and needs 15k in repairs. The second house needs about 10 in repairs. The seller was asking $26k but went down to $23k because there are two houses. So what should I be looking at for comps? Any advice is appreciated.