How to calculate ARV with no comps?

[Carmen Lewis]

I am doing some research (trying to) on a few properties in a rural area. They appear to need a full rehab, but I don't know how to come up with the ARV. There are no recent comps and the houses nearby vary widely in sizes and prices. The price ranges of the other houses are about 100k to 300k! So I don't have a clue as I am still a newbie and learning.

Also, are rural areas highly sought after? The area is beautiful and I rarely see houses for sale. So I just figured the few properties I came across would sell fast when fixed up.