Beginner Gardening: new landscape challenge!?, 1 by Crick22

Crick22 wrote:
I will post 2 pics but here is the problem--a big one. I am in zone 6b. western NC. I have a almost non-landscaped sloping property and I am from the flatlands. The yard here is about 25' deep (from top of ditch to deck) and about 47' long that I want to do something with. The slope described is, starting at the top and from bottom of deck rail to ground 18 inches and at the bottom end of the deck 7 feet high from ground to deck bottom. The ground slopes both towards the drainage ditch and downward longways of the yard. Oh, I put a red blob on my candidate poster in the yard as I thought I couldn't post it with it showing but did not want to go to the hassle of removing and replanting it. I hope you can't tell who it is. Well, maybe I do but it would not be 'kosher' here.
What I want to do is create a raised area in the middle of the yard between the tree on the left and the driveway and plant greenery and maybe a few flowers. But my main problem is the drainage/erosion issue and the drainage ditch. A friend told me to fill the ditch entirely with river rocks and put a grate over the drain holes so that I can lift it if need be to clean it in future. Of course, this sounds pretty expensive to me and there are lots of leaves that fall from across the road in the fall. I had thought about killing the weeds and grass and putting in some kind of ground covers or plants that would fill in the area entirely. But then I have the erosion/drainage problem not solved. A lot of moss is growing in the yard and I do not want to have grass there. Moss would be OK but I need to get the few grass twigs and weeds out. Any ideas at all for the overall plan? I will appreciate any advice--keeping in mind the limited budget of a retiree and a female with no muscle help except very occasional friend/family visits.