3 points I would make:
1 Financing: It is very difficult to find a lender who will write a mortgage for such a property without a recorded (or recordable0 'private road maintenance agreement.'
2) Actual road maintenance and accessibility: The length of the private road and your ability to do snow removal, and mud-ruts-control if the other parties cannot, or choose not to, attend to those issues might be a factor in your sale.
3) R.O.W.: Do you have a recorded right of way for the road wher it crosses other private properties?
As suggested, check these things out carefully, to assure that you will be able to have clear enjoyment of your property.
Hope that helps
If this is just a normal house, it may be less attractive because of no adjacent neighbors or kids to play with.