Getting our garden groove on - gathering knowledge

We are going to move out onto our wooded property in about 3 months.  We will be living in a travel trailer while we build our house.  Most of our efforts will be focused on getting the house built and ready to move in, but this isn't going to happen overnight.  As a part of clearing trees to make room for the house, garage, and drive, we also cleared an area of some leaning trees that posed a potential threat to the house.  This area has a southern exposure and gets a lot of sun during the day from around 7:30 AM until around 4:30 PM.  About that time it becomes increasingly shaded.  Since the entire acreage is raw woods that hasn't been touched in about 60 years, there is no shortage of leaves and fallen trees.  Currently there is a 6-12" layer of dark, loose, spongy organic matter built up on top of the clay sand loam underneath.  Anywhere the ground is exposed it is a matter of weeks before native grasses and plants start sprouting.  So far we have:

1.  Created a compost area where we have been piling leaves during the clearing process.  After the first few months of clearing I discovered Permies and haven't burned any leaves since.  We have been piling them in a compost heap, along with grass and greenery cut down before it went to seed.  Every couple weeks I dump in coffee grounds and vegetable scraps, then turn it.

2.  Selected an area to build hugulkulture mounds in a horseshoe shape.

3.  Began digging up the top layer of organic matter down to the the sandy clay layer.  I'm depositing this on a tarp and keeping it covered to put on top of the mounds.

4.  Cut several down trees in various states of decomposition and started moving them to the area I've dug out.

5.  Made piles of various size materials from trees we've had to cut down and dead fall.  Lots and lots of dead fall!

My plan is that once I get the first layer of larger tree trunks around 12-15" in diameter laid out (exclusively deadfall in varying stages of decay), I will cover with a layer of the compost we have been working on for the past year.  Next will come a layer of wood around 4-6" in diameter.  I don't think I'll have enough composted/mulched leaves left to cover this second layer, so I may have to have some topsoil brought in.  After that I'll start piling on brush and branches from topping trees, followed by an overall covering of soil.  

Since the work we are doing now is basically prepping for garden that won't be planted until 2021, would it be better to purchase soil or keep raking and piling leaves to break down?  I can put down the first layer of logs, then fill between them with the compost/mulch I have now and wait until I have more stuff ready to begin the next layer.  I doubt it will hurt anything to leave my piles of brush and branches exposed until I have more material to cover them.  This spring we are going to plant some herbs, tomatoes, and peppers inside the horseshoe area but don't plan on a big garden.  When we aren't working we want to put our time into building our cordwood home so we can get out of the travel trailer.

As long as we live here we don't plan on burning any of the leaves we rake off the ground.  They are too valuable as mulch and compost.

If you keep putting compost and leaf litter on your hugel, I think that by spring 2021 you will have enough soil to plant into.  The largest hugel I've.made was 6x12 or so, and the biggest thing I noticed was how much the hump settled as the wood rotted and soil fell into the gaps between the wood.  

The only thing I would add to your plan is some sort of cover crop over your hugel.  I really like to use organic 10 bean soup mixes from a bulk bin.  Most of the beans sprout if you soak them first, and where I live it is cheaper than buying a bunch of bean seed packs.  Since the main job of the beans will be to shade the growing soil and send roots all through the hugel, when you would add more logs and brush just cover up the beans to decompose in place and plant more on the new surface level.