In areas such as NYC the market tends to be a little lower, from what I understand.

Again, all answers that might be better answered in private.You are correct that a lot of lenders just don't understand how we work as investors but that's why some of us hang out here. 

New investors eager to succeed are impressionable which makes them easy prey.

I would hesitate to say 1-2 years to rotate out but closer to 5 years, and ideally I'd try to get the downpayment higher to at least 10%.I understand your areas though-- they're expensive.

Have read and done some preliminary research on assumable loans, and was wondering if you could help me understand the hurdles that go along with it.  

All, I understand that to be a property manager in Colorado you must be a licensed realtor. 

Understand you have great equity position but it is expensive, but more importantly  takes a lot of time and very distracting from other money making activities to foreclose.

You don't need to know everything to get started; you need a foundation to build on, and the rest will come through experience and then refining your education.You can build a basic understanding of investing in 3-6 months.

.- I prioritize building strong, professional relationships with my buyers by taking the time to understand their needs and goals.

Besides understanding the benefits of a free market, they also understand the ramifications of rent control.good luck