I strongly agree with Roberta's suggestion to reorganize but read on if you will.
Right up front I will say that the services of an attorney skilled in the matters of private road association structure will pay immediate dividends and perhaps the current board should consider (again) ponying up the cost of two hours of attorney time to settle the very first critical question I ask below. I am disappointed and not sure why the attorney you consulted before did not address the issue but it is a must start point.
When all is said and done, does your current association structure have the legal authority to assess, invoice, collect and enforce collection of road maintenance costs? If you believe so, what is it that you believe gives the association that authority? If not, then the board members are merely an amalgam of well meaning individuals that will need to sharpen their negotiating and problem solving skills because they have no power beyond persuasion and you can stop wracking your brain on bylaws issues.
If you want to lean on section 3121, good luck because that part of the statute says:
"a legal claim for payment of the amount owed may be brought against that owner by a residential property owner or owners who share a common benefit in the road, either jointly or severally."
One or a number of you must take the action personally. The section offers no hope for recovery of legal or court costs nor much else in guidance. In fact, just the existence of the nonprofit with bylaws and history of operation could totally disqualify the association from suing because, as Roberta said above, the statute only applies in the absence of an agreement.
Now to answer your questions: In my opinion:
Should the board step in override the loud minority and only offer fixing the by-laws or defaulting to 3210? The board makes decisions based upon what is best for the whole. If indeed bylaw changes are required the board drafts changes and calls for a vote. Otherwise you have anarchy that benefits none. And 3121 is briefly discussed above and elsewhere. It is useless for you.
Should the board just vote on what to do and make the decision? Regarding the level of maintenance, YES, if the bylaws so permit. The board is elected to govern and boards that get hung up trying to please everyone will be ineffective and will thus penalize the majority as well as the minority. The safety and convenience of your road and value of your property depends upon positive leadership. Of course, if the association has no legal authority to assess and collect they will also need creativity to cover the budget by only those who will pay.
What does it mean if we don't comply with the law? what are the consequences? None. You are not obligated by either 3101-3106 or 3121 to do anything! In fact, the Private Ways Act (3101-3106) is an enabling statute that merely says IF YOU DO THIS, THEN YOU CAN DO THAT. Meaning if you establish yourself as required by the statute and administer as required by the statute then you get the privilege of enforceability of your fair and equitable assessments. And once again, 3121 only applies to individuals, not associations, and requires nothing of anyone, only allows filing a legal action to collect.
If you think the bylaws are effective then you really need to read them carefully. Seldom do bylaws (seldom, not never) require more than a simple majority vote for routine matters such as setting budgets and assessments. And the vote may be limited to those attending (or proxy or absentee) not the entire membership. So take a careful look. Supermajorities are appropriate for bylaws changes but not for the efficient operation of a road association.
By the way, to become a Statutory Association no supermajority is required . "By a majority vote of the owners present and voting in person or by written proxy or absentee ballot, the owners may determine what repairs and maintenance are necessary and the materials to be furnished or amount of money to be paid by each owner for repairs and maintenance and may determine the amount of money to be paid by each owner......"