Filling vacancies and improving the rent rolls may be difficult.

All of the REIAs are great for early stage investors, but value becomes more difficult after that stage and learning to create value and a network beyond that is tough.  

Another thing to consider is that it may be difficult to find a lender willing to write a $30-40k mortgage.

I realize how difficult this would be, but developing house flipping into a seamless process would be extremely advantageous. 

It was in the heat of the moment but this unit was difficult to rent last time and I would like to postpone a turnover as long as possible.

You should learn how to analyze the numbers.If you don't know how a good deal looks like...it's going to be difficult to line up financing and equity partners for the deal.Do a cashflow analysis.Here's a good spreadsheet that I use (I uploaded it in BP Fileplace:Cashflow Analyzer

I definitely suggest connecting with as many local investors as possible, find someone who really knows what they're doing when it comes to finding deals, knowing what a deal is and funding, and you've got the potential for a great partnership.Like @William Allen said, and as I'm sure you'll hear on the podcasts and read on the forums, finding a great contractor is often the most difficult part of the process.  

It is very difficult to prove intent in those circumstances unless you have some pretty good documentation to support the intent to hold for investment purpose and to explain the short holding period. 

FNMA would have a difficult time selling the property now as the condition rules out anyone getting a loan This is another thread that illustrates the importance of having a great agent.

Maybe its me or the way I'm phrasing what I need when talking to insurance agents but it seems astronomically difficult to find loss insurance for a vacant property in DC.