You might want to consult an engineer for guidance on the retaining wall and any drainage affects so that erosion doesn't destroy your driveway or yard efforts, or possibly your home.

Easy peasy lemon squeezy if you have a couple of friends. Call for the diggers hotline first, though! Rent or borrow a backhoe and find a friend who knows how to operate it and get that dirt out of there in an afternoon. Or you can grab a shovel and get a good workout for cheap. Depends on your time frame. Craigslist is your friend- people are always looking for free fill dirt. A retaining wall is not that hard if you use those interlocking stackable blocks, but it’s a fair bit of work. The blocks are readily available and affordable, and you can start buying them in advance to spread out the cost. YouTube some how to before you start. Be sure to include drainage- common and ultimately costly mistake. A french drain in behind the retaining wall and some gravel is a must. And honestly, that isn’t too much concrete, if you go that route. Less than $500, probably. If you do go with rock, use crushed granite over larger white rock or similar material. It’s a lot more stable than gravel.

Yea I have a few buddies to help me dig out the area so that's not an issue. I'll take a look at the interlocking blocks and drainage ideas. Thanks so much for the replies

I would not begin any work on this project until you've converted it into a clear, simple plan that shows the complete extent of work. It should have dimensions of proposed work called out on the plan and materials stated. Lot lines should be on the plan so we can see how much space there is to work with.

The pictures do not give a great idea of the existing grade. You show across slope in order for the camera to pick it up, and sufficient background should be included so that it is clear how the area relates to the larger yard. It would be good to see how this parking & path connect to the house in case there is something being overlooked by the design.

From the description, I'm confused about what you're going to end up with. You are ADDING 14' of width? ... or adding enough width to create a total of 14'? The cars seem to clear the public walk so why are you adding 9' greater depth to the parking spaces? Maybe a little would help but 9' seems to be creating complexity and expense.

Many/most communities have tight restrictions on parking areas within the front yard. Be sure to run your plan by the municipality to make sure that what you're doing is allowed. Or they make you undo it.

Personally, I would be against expanding a concrete drive with gravel. It will be an automatic downgrade in appearance as the gravel looks rural and is messier. I'm not sure how you're planning to contain the gravel, but it must be figured out so as to know the complete project. I'd stick with the concrete and put the project off for a while in order to get the right material. Or find a way to break it into phases to make it do-able. Another thing that is unclear is how cars will access a wider parking area unless the drive apron is widened. This should be shown on the plan, too.

In many cases, people use groundcover on slopes so they do not have to cut grass on slopes.

Did you consider terracing the area and planting with a mix of shrubs/groundcover/ perennials? I have seen that approach used several times in my area with excellent results. Keeps the slope more stable than excavating and building a retaining wall too.

An even large parking area will not be any more attractive than the slope IMO, I assume you have a real need for more parking?

That doesn't sound like to bad of an idea. Any pictures I can refer to get an idea of how it looks? And it's more of a want than a need. I wanted to get another car for me and my son to work on together and didn't want to rush to title it so planned on keeping it in the driveway

I would replace the turf with shrubs rather than a low groundcover. It will hide the cars and parking area, which most would agree is the eyesore.

You need a retaining wall 100% if you plan to cut into the hill as outlined in your pictures. There's a massive amount of soil that will need to be excavated and hauled out in order to create another parking space. Also, I wouldn't trust a family member to help build a wall for this location. Retaining walls need to be build properly, especially if you are parking your cars below them. So many walls tip forward and buckle because of improper foundations under the wall and improper drainage approach behind the wall. This is not something you'd want to spend a lot of hard work doing for it to look like hell in a few years and eventually have to pay a pro to redo. I'd highly recommend get estimates from landscape contractors and start saving for this investment project. Just by looking at it I would say it's anywhere between 10-13k from a contractor.