Adding fill for parking

[Pulleye16]

I don't have a lot of space for parking at the cabin and would like to add some fill near the driveway, so I have both more parking spots, but also an easier route to backing trailers in the garage.

Off my driveway, it quickly drops about 4' over 20 feet in length. My gut tells my to build a retaining wall with some type of water drainage system and possible anchor the blocks (since parking on top). I want to add about a 20'x20' parking. Guessing it'll be roughly 4' high of fill at the lowest point (edge).

Would this be the best option? Would tapering off the fill be better (and probably way cheaper)?

Other option?

FYI-it's not considered low land or swampy but I'll be checking with the county prior.

[LPS]

Sounds spendy with the wall but only you know what to do.  Or mayhaps the wife.  LOL

[Bonus]

Tapering the grade may be the least expensive option but it will use up more land than a wall will.
Will you need a culvert under it?
Whether you need or want  the area for other purposes and how it effects the natural drainage should be the deciding factors.

[Scenic]

With the cost of delivery for dirt these days you might be better off with a retaining wall.  It actually might be cheaper.  20x20x4 is a lot of dirt.  Just doing it in my head you are looking at what 60 yards?   To taper that would require a LOT more dirt to get it out far enough.  If you taper it the best bet would be to plant it as quick as you can so you might need some black dirt over the fill to get stuff to grow.  In the long run you will need to mow that taper as well...maybe.    You can use fill for probably all but the top 2'.     

[Rodwork]

Will be following as I am also looking at extending my driveway for more parking. But I would have to use retaining block to keep the property line the same 5’ away. Also have a 4’ drop for me. Building the retaining wall is not hard and I believe if it is under 6’ tall it doesn’t have to be engineered. (I need to double check on this.)