Land Plane for sure - I maintain a mile plus of road that is a mix of ledge, boulders, sand, and gravel. I previously used a box blade, landscape rake, and rear blade.... and have occasion to use all of them still. BUT the implement that has made the biggest difference, and really does most of the work, is the land plane.
I typically do the following:
-in spring use the landscape rake to get all the winter debris (road isn't plowed in winter) off the road as well as out of the ditches (8' offsetting Woods rake)... leaves and sticks mostly
-Land Plane, followed up by a medium-speed raking (the land plane brings lots of stones to the top - the small ones I want to keep there, the not so small to large ones I want OFF the road, and not in the ditch either. So a good pace with a very angled rake just barely touching the new surface works great to pick up and fling those rocks right off the road).
If I lose my ditches (folks "mud bogging" in there in spring) I'll use either the rear blade to move the material back in to the center of the road (and re-creat the ditch) or if it isn't too bad the landscape rake. The box blade is also good for moving material - but really not as good for getting things super flat easily. I use my box blade for making NEW roads mostly.
Another "implement" if you will I couldn't live without at this point is top and tilt - it makes road maintenance SO much easier being able to adjust on the fly both the land plane and especially the landscape rake (being able to "feather" areas). I do have the gauge wheels.