A few questions.
1) You say the road association now owns the road. Was the road actually deeded to the association by the former landowner, or do you simply mean that there is now a road association that has assumed responsibility for the road?
2) Is it a Statutory Road Association established under 23 MRS 3101-3104, following the proper procedure for notifying the owners of all benefited properties?
3) Do the owners of that last lot actually use or have any intent to use the road?
I can give you a better answer once I know the answers to those questions.