The area where our yard meets the ditch & county road is similar to your issue. I have to mow from the top with a field trimmer over the edge & down alittle. Then to the road & mow that part going up as far as the trimmer will go. This stretch is about 200 feet long so it is time consuming. And there's always a middle section that I can't reach from either side. For years my husband would weedeat and burn it but he's disabled now. I don't trust burning by myself an area that big so I've been thinking of what I can do.
I tried planting a few bulbs like jonquils thinking as they multiplied they would crowd out the weeds. Nope. The weeds just hid the flowers.
Since I'm getting older I need to think about how I'm going to do the upkeep on anything. So I want to be like the old Ronco commercials & "Set it & forget it". So as soon as I get the money, I'm thinking about doing this:
My plans are to have railroad ties at the very top & very bottom. Spray everything with Roundup or similar, maybe cover with cardboard to (1) try to protect bees, etc. & (2) keep anything from coming back. Get dump trucks to unload rocks & lay chicken wire over the rocks to keep them from shifting. The chicken wire would then be under the railroad ties.
The neighbor's water meter & a fire hydrant are in this area so for easy access to these, I'm thinking something like this: