Wow! Thanks for all of the suggestions. I'll try to answer all of the questions.
I fly a powered parachute. Its a 3-wheeled cart with a pusher prop on the back and a parachute for a wing. Its critical with these that you always land and take off into the wind (unless you like tipping over). By making the whole 15 acres a runway, I can always take off or land directly into the wind rather than being constrained by a runway. Its a convenience more than anything. I could get by with two perpendicular runways but the big field would be a whole lot nicer.
I went out this evening with my old Farmall H and did some dragging. I discovered that by going over an area multiple times with the drag that it brought up a lot of sand and did a pretty fair job leveling. In some areas, you couldn't see any grass any more.
After seeing how the drag was able to work up the sand, I'm convinced that I could probably use a disc followed by a drag rather than tilling or plowing.
One of the concerns that I have is that my JD 3020 (which is what I mow with) is pretty heavy. If I loosen up the soil too much by tilling or plowing, then get everything level and the grass growing nicely, I'm worried the first time I mow the tractor is going to rut everything up. Whereas, if I lightly disc the top, drag and seed, I'm wondering if the ground won't be more solid and less likely to rut when I mow?
I do plan to spray round-up but not until after the grass in the field starts to green up. My farmer friend explained that round-up works by getting into the roots and only works when stuff is growing.
Lets say I do disc and drag....I was planning on seeding with a brillion because I can't find a no-till drill. The brillion does require really loose dirt (sand) to work, doesn't it? Would I need to go over the field with a cultipacker after using the brillion?
I'm sorry about all of the questions. I'm trying to educate myself and do things right. I'm going to get soil samples tomorrow and drop them off at the local feed store.