Landscaping?

We would love to have a yard and better area for Roland, but do we want to spend the time and money? It's a lot of work, but then again we know we're capable. Last year we put in a treated wood 70 foot retaining-wall raised garden, and a brick retaining wall path in just one weekend. I've sketched out some rough plans from an overhead view. The things that don't currently exist are:

• footpath
• boardwalk
  
• brick steps
• lawn
• fence

The fence is about 500 feet long. That alone could be a lot of work!

Click for a closer look (updated with dog house and split rail fence):



Below is a cross section of the dirt work plan to flatten an area. Essentially I'd be cutting out a triangle from the top and placing it on the bottom.

Update:
I've made an updated version as an option. This moves the yard higher, more accessable from the house. It should work as long as there is a row of natural trees between the steep slopes below the parking area and above the lawn to prevent any erosion

The darker shaded grass represents the steep slopes, and the lighter shade is the usable lawn area