How do I figure out the ARV if there are no comps ?

[Kasia Harmata]

I am looking a certain neighborhoods and looking to find the ARV's for 2,3,and 4 unit buildings. For some of these, I can't find comps, even by searching as far back as the MLS states. If I buy a property, renovate, and refinance -- how will the appraiser figure out the value?

I have also broadened by search, but having the same issue. Another problem is that the property values change block by block.