You mentioned oaks. Is the ground heavily disturbed, like removing large stumps. Many places have a relatively thin topsoil section, and lesser quality stuff down deeper.
Rye is a great plant for low quality soil sites, if your site is one. Rye grows taller than other plants. You can use that tall stuff as a trellice for viney plants. Hairy vetch is good for sandy soils. Peas will climb up the rye too.
I always put legumes in any planting. Helps make nitrogen. Keep it simple with medium red clover. I am still researching clovers for sandy soil myself. But medium red does ok.
If you suspect your going to have deeper soils sruface to the top, get that soil tested. Keep in mind sandy soil takes alot less to steer it around than clay soil does. Top raise soil pH or add nutrients like potassium or phosphorus, the sandy soil doesn't hold alot. Got to go slow with sandy soil.
Get a deep layer and get a topsoil one. Stirred up soil is going to be a mix.
Ive seen good spots turn almost barren with a good stir of a bulldozer.