can you show a picture of the overall area and one of the gravel? By "item 4 gravel" do you mean #4 gravel? It's being course, I would not want that as the final surface. I would not mix mulch type products over stone base. Also, say who is using this parking. It it a private family area ... the public ... who and why.

The parking area is for very occasional use for guests (actually an upcoming wedding :D ). This is the surface we will be left with. It's a packed clay that will dry. The landscaper/contractor says it will grow grass and weeds, so i'm thinking maybe the best option is to spread grass seed, and if it gets too wild just weed whack it? We will put some huge locust tree trunks as a barrier on the edge. The slope is dirt-covered rock that should probably also be sown with something. Thanks for any suggestions for making this more attractive.

Why not grow grass since it's for occasional parking? Mow occasionally to control weeds. Can't advise on berm planting/screening since this doesn't show. (The picture is a bit close-up.)

Thanks, Yardvaark. The berm idea has been nixed in favor of the locust trunks for now. What do you think about growing climbing hydrangea on the existing maples and locusts that are now about six feet downslope? I ask because we have it elsewhere on the property and it works to turn bare tree trunks into dense screens. I am afraid to do ivy or euonymous (which we also have doing the same thing) because they are so invasive. I will take your suggestion about the grass, and will appreciate any guidance on the type that will be most successful in this shady area and will be most likely to stand up to the occasional parking..

It will be better for you to get grass recommendation from someone familiar with local conditions & plants. If you have too much shade, though, it will not work, or work well. (Cannot gauge light conditions from your photo because it is so close-up.)