Obviously this is only my opinion, but to be clear, you are asking about maintaining the road. .
Is your road on flat ground, or do you have inclines that you have to go up? If flat ground you may be able to get away with a 6 foot wide grader, but if you have to go uphill, I would stay with a narrower blade, 60"-66" I would think. If you consider a grader type of blade, check around, there are several makes and check the weight of them, the heavier the better for this type of work.
yes maintenance. Va Mtns incline.2/3 is relatively" flat " ( this word is not used in this area much) I have been maintaining it for the last few years with my Dodge 2500 diesel and a 16' flat bed with 2' side walls trailer. I go to the quarry 2 3 times a year get 4 to 5 tons of crusher run and then hand unload with a shovel.Last year I ordered a load 15 to 17 ton and had it track spread. The quarry has a device they use so when the driver unloads it puts the crusher run in the two tracks not in the middle, I do the same with a shovel,as you can imagine one has to man up for this task.Anyway the snow this year convinced my wife that a tractor would be a good investment.I posted in the attachment section last night a conversation with a Kubota engineer yesterday specific to a rear blade on a Kubota B7800.Their recommendation is a 5' standard duty back blade anything other than this rec can result in damage to the 3 pt hitch and components.I would still like to get a 6' blade to help with ditch maintenance.The 5' has an off set maybe the best choice ?