Thanks for the question.

It sounds as if you have a rather big project facing you. I would suggest the following:

1), For this area, cut down and remove as much as possible all trees, shrubs, and brush.

2). Then again to the extent possible, dig up and remove as many of the roots as possible. You will not get them all. Do NOT do any tilling as this will just create root fragments that will result in more things growing.

3). Spray the area with a herbicide containing glyphosate (e.g., Round Up). This will kill much of the vegetation that may still be exposed. Be sure to follow the application instructions on the herbicide label. Repeat this herbicide application in early to mid-September.

4). In early spring (mid to early April) depending upon the area involved, consider adding two inches or so of good top soil and processed compost.

5). Also in early spring 2022, distribute a pre-emergent herbicide (e.g., Preen) over the area with the fresh top soil and compost. This is to prevent any weed or other seeds from germinating.

6). Now you should be able to plant whatever cover crop(s) you decide upon. Here are some possibilities:

Bunchberry Dogwood (Cornus canadensis) 

Creeping phlox (Phlox subulata)

Dwarf red blackberry (Rubus pubescens)

Bigbract vebena (Verbena bracteate)

Eastern woodland sedge (Carex blanda)

Also look at:

https://northerngardener.org/great-groundcovers/

https://northerngardener.org/great-plants-for-northern-gardens-day-23-groundcovers/

Good luck and please get back to us if you have any additional questions.