Grow steady and have a strong foundation.

Home built in 2005. 

The vibe of Biddeford has gone from burning garbage in a decimated downtown, to boutique hotel and trendy restaurants in very few years.The apartments in town were built for mill workers a long time ago.  

Hold it for few years and then sell it or built a second/vacation home. which area would you recommend and why?

These do require more time and organization though.Looking forward, after 5+ years of owning a property, assuming you bought in an appreciating area, you should have enough equity built up via tenants paying down your mortgage for you and appreciation to refinance out of the VA loan (if you haven't already) or even cashout to buy more or to supplement your earnings.Theoretically, if you have enough properties you could refinance at least one a year.

Do you have 2-4 contractors that you've built relationships with who build similar homes to what you're looking to do?

It was built as an office building in 1888.

What I've seen before is the only time rules are enforced are when neighbors get pissed (ie STR neighbors).I would side with caution on this, especially if it is a newer built community where the rules are fresh with people. 

Here are my thoughts about your decision to refinance.Process:Understand your current loan terms.Check your credit score.Compare offers from different lenders.Get your property appraised.Submit your application and go through closing.Considerations:Current interest rates vs. your existing rate.Amount of equity built in one year.Closing costs and fees.Your long-term financial goals.It's a complex decision, so consulting a financial advisor or mortgage specialist might be helpful.

However, if the deal is average, waiting to house hack could provide a better foundation for your portfolio.