Hi Nick, welcome
One thought is that 20 acres plus a full time job, equals way more than one man can manage. I would reccomend starting much much smaller. The beauty of permacultural farming is that you can do so much more with so much less. I personally farm 12 acres, sole source of income for both me and the wife, and it is more work than most reasonable American couples would entertain. We arent reasonable, so it works for us. Too much
land and too little time means neglected situations, and excess stress. Quality over quantity will win every time.
And if you really want this life, ditch the three year plan. Get on it now. No excuses. I for one wouldnt spend three years working a piece of temporary land. If you have a dream, follow it, today. Tomorrow never happens how we hope.
good luck!