I bought an old farm house and about 9 acres of land, it had been worked pretty hard and had rows you could still see. In the front of the house I tilled it and leveled it. In the back not so much. I cut it all, I like it that way, plus it keeps the ticks, snakes, and mice away. Tons of birds come onto my field after cutting and eat the snot out of the bugs.
My .02, just make sure to cut and cross cut it when mowing. The clippings will eventually start to fall into the ruts and before you know it the ground will level out a bit. Fill in any large holes. Just take down any real high points. The first 2-4 years cross cutting was like mowing a washer board. Now I have more issues with my tractor rutting up things than anything else. Get the biggest mower you can if you cut it all, I started of with 6, went to 7 and wish I had 10. I also have a zero turn that flies across that field.
One other piece of advice was given to me, guy said rather than buy topsoil, go to the back edge of your land and scoop out the top 3" about 10' wide and use it on your field for small areas to fill in or level out. He said it would regrow in several years. He was dead on the money and saved me a lot of money on buying soil. I live in the mountains and all we have is clay, shale, and sandstone. Ohio is a little more fertile flatland, so topsoil might be cheaper there.
Good luck.