5 Unit Commercial Property a good buy?

[Matthew Langberg]

I'm about to quit my day job (I own a profitable business as well) and cash my 401k to invest in a 5 unit commercial building built in 1983 in one of the highest traffic areas in my town. (Fairbanks, Alaska) Purchase price is 1.1 million. Monthly income of 20k, (which is 30% lower than comparable properties in the area) monthly expenses, including mortgage and insurance are 16,800 assuming a 10% vacancy rate, 15% repairs and maintenance and 15% towards cap ex. which are all very conservative estimates as the property is in great condition and has been well maintained and all units are filled with multi-year leasing well established businesses. This will leave me with a $3200 per month cash flow, and just under 20% cash on cash ROI in the first year. Seems like a great opportunity to me, but as this will be my first investment of this proportion I wanted to see if anyone could poke holes in my assumption. Thank you in advance for your time!