Do you have access to a box or other type of rear blade? When I leveled my pasture I placed piles of topsoil everywhere there was a depression. I then attached a 12' 4x6 under my box blade (blade riding on the 4x6) using bailing wire. Then just pulled through the piles working at various angles (like grouting tile). I did need to re-attach the 4x6 a couple of times, bur it worked great. As I worked I used the tractor to compact the soil. Later I fertilized and seeded, and then used a drag harrow for the final finish.
BTW - that 4x6 has come in handy numerous times for other tasks.