We're hoping that we can manage to get tenants to turn over in the summer, where we can spend a couple of weeks down in DC combining a little vacation in the place with fixing things up and finding a new tenant).Of course I made some mistakes already, too, but I think I'll get away with them this time...So after getting my feet wet, I've been reading about REI, and we do have cash / equity (our primary home is just about paid off) to stuff with, so now I'm considering to get into it in a non-accidental way, and it seems more prudent to look at our local area (NH seacost), but it turns out I have little idea about the purchase/rental market here, and it doesn't seem all that easy to find out (in NoVA, at least, there's a very active market, while here prices seem to fluctuate wildly for no obvious (to me) reason.

From what i read there seems to be a little more positive community development there.

(I may also be able to pull a HELOC on my primary home)I will rent the property between $1200-1400, I will immediately get a LOC on the rental property to pay off my personal LOC and Credit cards.

It was a former primary residence that my wife and I decided to rent instead of sell.

We have one of the most undervalued purchase markets and one of the highest rental markets, a good recipe for success if you position yourself correctly. 

The Short answer is this: While you are correct that you would be paying down the balance of the mortgage you would not however be in a position to pay for any surprise that might come up and need you attention and you money...

Depending on the lease you used your document may have a transfer of ownership clause or something similar which requires your consent.If you do not have a personal guarantee or some sort of material change or adverse change provision, I am not sure what recourse you may have with the sale of the business operation.

If you think you'll sell your current properties in a few years, build up the equity and pay them down now so you can be in a better position to roll the money from those sales into other properties.

How does the market look for appreciation in your equity position in the property? 

If the new Buyer reneges, that might put the OP into a better bargaining position!