Its tough to mix a conservative fiscal mindset with a desire to aggressively grow my portfolio, but I'm sure I will find some safe middle ground along the way. 

Always under write very conservative, in other words always prepare to pay more for interest, taxes, insurance and at least 4k a year in maintenance per door.

And no, cash flow alone will not save you, nor will equity alone, nor will reserves alone, but a combination of all three ... but how much and in what proportions is the million dollar question that only comes with time and experience, so air on the conservative side until you have that. 

It is extremely conservative, more like forced savings, and the funneling of rent into the mortgage pay down is probably twice the value of the home unless he is in a market that is appreciating rapidly on a continuous bases.His method may work but produces negative cash flow over the long term during ownership.

In general, be conservative when you buy and keep in mind how the general economy might affect your strategy when it comes to financing terms.

Most conservative folks will say that if you hold at least a year you are in safe territory.  

I am in process of speaking with the township, but given how slow they move, was hoping someone with knowledge could point out the important aspects, especially around the conservation easement, as I try to understand if I can clear trees out to expand the backyard.

Operating costs I try to estimate somewhat conservative= $1000 a month.    

But 10% down is certainly not the "conservative" approach. 

Built in 1973, in great condition, although does not have current upgrades.Since I am not yet a PRO user, I based on my rental calculations using great calculators from ListenMoneyMatters.com.SUMMARY:ESTIMATED VALUE (Zillow): $214,714.00 (In line with averaged real estate agent's Comps but slightly more conservative, as I think he threw in a couple outlier properties to bump the average a bit to entice my folks.)PURCHASE PRICE: $195,000.00 (price based solely on the amount left on my parents 4.25% HARP non-assumable mortgage)UPFRONT COST: $50,587.42 RENT ESTIMATE: $1750.00 ANNUAL NOI: $11,633.00GROSS YIELD: 10.79%CAP RATE: 5.98%CASH ON CASH: 5.56%CASH FLOW:ANNUAL: $2760.32MONTHLY: $230.031ST YEAR EQUITY: $2363.49ACQUISITION COSTS:DOWN PAYMENT: $48,641.75 (25% ) CLOSING COSTS: $1,945.67 (1%) *anticipate only using real estate attorney (no real estate agents) for more cost effective deal and save parents 6% commission; do not know actual attorney fee costs for closing so this number is a WAG (Wild *** Guess).MORTGAGE RATE: 4.5% *anticipated MORTGAGE TERM: 30 years ONGOING COSTS:PROPERTY TAX: $1,927.00/yrPROPERTY INSURANCE: $300.00/yr PROPERTY MANAGER: $175.00/mo (10%) VACANCY RATE: $350.00/mo (20% vacancy rate)MAJOR/MINOR CAPEX: $175.00/mo (10%)HEAT/AC: $92.00/mo (Averaged)HOA: $420.00/mo (has remained approx. $420.00 for decades; although the HOA just hired a property manager for the first time last year, but so far no indications of changing HOA fees)Notes:Rent estimate: $1,750.00 (local property manager assessed realistic rents between $1600-$2000+ per month on long-term lease or as vacation rental $140-200 a night/minimum 1 week stays).My parents are open to any type of creative financing deal, that would free them from paying mortgage (their current monthly mortgage payment is $1,000.00 (+ $420 HOA).