Hi, and welcome, from Southeast MO. You can learn a bunch on here and really impress your fianc!
Let's see....If I were plowing up new ground now, I think I would want look at a small section before doing the whole thing. If you have rich alluvial soil like Bluejay77, you may not need to amend it much, if at all. If you have heavy clay like I do, you will want to add organic matter at every opportunity. Like maybe adding a truck load of manure now, and tilling it in. It could be fresh manure, because it would be aged/composted by spring.
Also, be sure to plan on allowing lots of room for the pumpkins, melons and vining squash. Maybe put them at opposite ends/sides of your garden, to avoid some of the confusion.