Mortgage banker here - for them to get a mortgage, they have to have legal access to the parcel and some kind of agreement on who is maintaining that access. If you are on good terms with your neighbors, and they have a mortgage, they likely have title insurance which covers this very circumstance and may pay you for the market rate of what that easement is worth. I would have them talk to their title insurance and the attorney they provide, and you should call your title insurance policy as well. Everyone involved has already paid for an insurance policy to cover this circumstance, use it!
Edit: I will also note the road maintenance agreement is not something you are obligated to in Virginia, at least. There is likely some legal right of an easement somewhere, but they have no legal right to make you maintain it. That is mortgage specific, and on all my transactions where someone is buying a property with a private road, I set the expectation with my client that in order to get a loan on this, the bank needs to know the collateral is going to be accessible in a way that maintains the value of the property. This benefits them by being able to get a loan and benefits their neighbors zero by being legally obligated to do something that they were not previously obligated to do. Occasionally the neighbors will sign such an agreement to record, particularly if one is already in place that simply needs to be modified in some way, but 9 times out of 10, the borrower just records an agreement with their deed saying they agree to maintain the private road sufficient to provide access to their own property and moves along. Expecting people in a residential real estate transaction to conduct a whole city planning project and get people on board for unknown future expenses is not real life and I can count on one hand the number of times I have seen it actually happen. If anyone thinks you’re going to sign something agreeing to maintain that road that you don’t need in any way, they are either crazy or new at selling rural properties.