My credit score is pretty high, like in the 800's.My problem....Last year, I decided that I wanted to try to buy more property so I applied for an equity cash out on my rental.

I was just back home last week and saw what my friends were doing back home (investing in OOS) and thought I should apply it over here in the US market.  

Does this apply to northern Virginia as well which is where I live?

If I have to abide by the limit, then the economics do not make sense.However, CMX-3 zoning allows me to apply for permits for a single room occupancy (SRO) purpose and a Visitor Accomodations purpose, thus allowing me to rent it out to more than 3 unrelated people at a time.

So now we have this money and I am questioning if we should apply it to an investment.

I have met with my banker 2 days ago to discuss my options to refinance when he asked me why refinancing and paying closing costs again instead of applying for a line a credit on the properties.Refinancing or line of credit, which one would be best to get my cash out to acquire more properties as an investor?

Math was my worst subject in school, but now that I can see how it applies to real life, it's my favorite thing to do.

First things first: Cap Rate does NOT apply to things like SFH's and plexes. 

But local governments are allowed to license and inspect properties.While the proposed changes would ban ordinances that specifically target vacation rentals, cities and counties would still be allowed to pass ordinances dealing with noise, parking and trash, so long as they apply to all residential properties, the bill’s supporters stressed Thursday.Much of the debate on the proposal focused on the property rights of people and businesses that own the vacation rentals and the property rights of neighboring homeowners.

The spread will be your profit and you can apply your 70/30 rule here.