Can I use a 4 plex to gain leverage at a faster rate?

[Harry Aiken]

I want to save 20%-25% down payment for a 600k 4 plex. I plan on it living in it and paying 80% of my w2 wages towards the mortgage. Assuming this 4 plex can generate 48-60k gross income per year, this could mean 70-100k/year pay down on the loan. Id like to pay it off as quickly as possible so i may sell it or refi the property to jump into 2 million plus. Scaling up. Is this worth pursuing? I helped run my fathers trailer park of 30 homes. Taking Rent, screening tenants, lawn care, did a lot of remodeling. I'll use the rent money to cover mortgage, insurance, property Taxes, all other expenses. Cash flow will go into an expense/savings account until the property can be paid in full. What am i missing?