It's tough to give much of an opinion without actual numbers (the value of the house you have now, the loan balance & rate, your current piti (principal, interest, taxes, & insurance + mortgage insurance where applicable), rent from upstairs tenant (you're declaring on your tax return so you can use it for your next loan application, right?).  

Plus, it's really tough to cashflow in this market, unless you can find a small multi-fam with value add opportunity (I've got one at $900K). 

For general information though, I think the Best Ever Apartment Syndication book by Joe Fairless is tough to beat for an all encompassing apt syndication book.

@Anthony Thompson most of my deals/network is in Boston however RI is looking promising in a few sectors primarily STRs in Middletown, College/summer rental combos in Ganset (regulations are tough though) and rehabs/LTRs in parts of Providence

My opinion is that for the Lakes Region, STR is a tough equation in terms of ROI in our limited experience.

But at the prices you are paying now I think it would be tough to ask for big appreciation gains. 

You should figure out how much it cost to replace each component of a house in your area using builder grade material and the lifespan of each component.

It may be tough to qualify for a loan with a part time job, so I’d talk to an investor friendly lender about what options you have.

Destroyed may be a little exaggerated but material cost might be covered by deposit, with myself doing the work.

Its tough, but try to build a network with other contractors, you should know the approximate cost (incl labor) to fix a leak, broken shower, caulking the bathrooms, rekeying your locks etc.