It is quite the prospect, isn't it?
Seems to me that I would begin looking at windbreaks, what to put in them and where to place them. Gaia's Garden has helpful discussion about what they do, how they do it, and what the area impacted by a given windbreak will be. I would recommend getting a copy of the book (2nd edition is slightly expanded over the first) for many reasons, but the discussion of windbreaks alone would make it worth your while.
Wind is probably your biggest single issue. You've got a largish piece of nearly flat land that gets a reasonable amount of water, but that is just naked to the winds. Those winds are going to dry your soil, blow your soil away, and bring onto your property any contaminants that are being used upwind of your property.
My second issue would be that ponding of water. Obviously your land is only "nearly flat", so the question of just what slopes there are and where they run is one you need to determine. Can you capture water and hold it in a pond at a high(er) point on your property and prevent the ponding in the low areas that way? Depends on your topography. Is water running onto your land from your neighbors, and if so, where are those flows running and what can you do about capturing them?
Geoff Lawton has a video about how he designed a 5 acre property that has some really good discussion about managing water. Even though the property he describes in the video has more texture than your parcel, the concepts are well expressed and apply to almost any situation.
I think it is never too soon to start planting cover crops for nitrogen fixing and biomass, including the accumulators that pull nutrients from deep in the soil. I would start putting those any place and every place that was not under lease or already under cultivation with another planned crop. Consider the cover crops as part of building your insectary along with your soil, as the various blossoms will start pulling in pollinators - and all the other insect life, both welcome and not, that are needed to reach balance. The cover crops are sacrificial in nature, so if you plant them over an area that later turns out to be the right spot for your herb garden, or your peach tree guild, or whatever, it's no big deal to displace them, and they have given you a headstart on getting your soil pumped up.
With such an open canvas, you are free to think broadly about things like sun traps that will help you grow things your zone normally would not support.
Now is the time to think about some other broad strokes regarding your overall focus. Are you looking to do significant pastured livestock, or is the focus of your land going to be on plants? If livestock, then you want to look at how best to organize your pasture, what processing you will need to do and where to set that, what housing will your livestock need and where are the best locations for it, fencing options, feed needs and how best to meet them (pasture year round, hay in the winter, grain supplements?). I am sure I am leaving out critical elements, but hopefully you see a direction.
If you're going to focus on the plants, are you looking for cash crops, food for your family, both? Are you thinking food forest or something less tree centric? Would you be picking and processing, or would you consider a U-Pick operation? These choices will likely impact how you design your plantings and definitely have impact on your time lines and needs for infrastructure. If it's just for feeding family then you won't need to deal with commercial kitchen licensing or setting up some sort of check-in and payment process for folks coming in to pick blueberries. If you're thinking food forest then the timeline stretches, with a short term set of plants for the near future that will give way to the longer term plants of the more established food forest.
Access is an early design element, with you needing to consider how you will get to the various parts of your design. For example, it would probably be unwise to run a major pathway through that area that consistently ponds up
Some thoughts off the top of my head, for what they are worth.