Good news Virginia, the solution to your problems is at your fingertips. You mentioned that there is a recorded maintenance agreement. That was easy for me to find. Luckily, your deed mentions the agreement and it applies to all 4 lots on your road. The deed, too, was easy to find. I have sent a copy to you via the private email mentioned in your member profile just to be sure you have the recorded documents.
Your property was formed by subdivision approved by the town and all lots are "....subject to the terms and conditions of the Road Maintenance Declaration....." The Road Maintenance Declaration is an agreement "...binding on the owners of lots 1through 4....." the owners ..."jointly and severally agree to be obligated to maintain, repair, plow, sand and replace the road so that it is reasonably safe and maintained in a good and passible condition...."
The Declaration states that "....all decisions......shall be determined by a majority vote of the Voting Owners", it permits the owners to appoint one owner as a manager who can act on behalf of the other owners. It defines the cost apportionment for each owner as 1/4 of the cost of maintenance and provides for binding arbitration in the event of a disagreement with the cost of arbitration split 50% to those owners filing for arbitration and 50% to the owner (or owners) against whom the arbitration is being filed.
The Declaration is quite specific, easily to understand, carry out and enforce. I suggest you call a meeting of the owners, have a clear agenda that spells out the process of awarding contracts, establishes a maintenance budget for the year, appoint a manager, then vote on the matters in the agenda.
The Declaration does not say how votes are take, when meetings, if any, are held or how to legally notify the lot owners. I suggest you follow the provisions of Maine's Private Way Act that requires an owner list be obtained from the municipal tax assessor and that meeting notices, at least for the first meeting, be sent by first class mail to the address on the assessor's list. Take Roberta's advice and read through the material available on the Resources tab.
I suspect that if handled properly the dissenting owner will fall in line and pay what is due, especially when the dissenting owner realizes that the owner will pay 50% of the cost to arbitrate the maintenance costs that the owner is clearly legally obligated to pay and will be responsible for 100% of the cost to collect, including legal fees, if the owner continues to fail to pay.
By the way, you and your neighbors will have to initiate the arbitration, not the nonpaying owner. But if you do it as a group the three of you will pay 50% of the cost and the nonpaying owner will pay the other 50% according to the Declaration.
So many lot owners along private roads in Maine do not have all that is available to you by deed restrictions. Take advantage of your good fortune.