I have been building/maintaining my 1/4 mile road since 1982.
I have used, at different times, 3 different rear blades, a box blade, and a landscape rake.
Taking care of the driveway did not become easy, until I built a landplane.
IMHO, you will not know exactly where the culverts are required, for a year or more.
Plan on installing them later.
If I were to build that road (my tractor is about the size of yours), I would shape the road with the landplane.
This might take 3 hours, it might take a day.
Then, I would roll the road.
My roller is a small DIY,, 1/2" thick ductile iron pipe full of concrete,,, it is perfect, for me.
Once I got the dirt base VERY stable, I would add 6 inches of what we call pug,, or mill run.
This is what the state (Virginia) uses around Roanoke as a base under new asphalt roads.
If the driver tailgates the material properly, you can then roll the material.
Next, shape the road again with the landplane.
Roll the road again,, and enjoy.
I lived in Charles City for a while, and built a lot of road in similar soil conditions.
If you use crusher run, you will need a large stone base, to stabilize the road.
Pug will seal the soil away from the water,,, without the pug, the road can get spongy from rain.
My road is closer to concrete than gravel,, the pug REALLY packs tight.
If you spend less than $2,000 for a landplane, it is too light.
If you want to build a landplane, there is a thread on how I built the one in the pics,,,