After you get your website up and runningYou would need trafficPurchase from a variety of reputable providers~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~bookmarks small quantitiesbacklinks small quantitiessocial media small quantities (plus ones ,, facebook likes , pinterest ,, etc)never over pay for seo servicesdetermine best local keywords for your future site as soon as possibleMake sure to avoid loud colors just like a rehab property – colors // tones - to appease your audienceCheckout your local competition (web page layouts )Basically get your website to rank locally ASAP ( that will assist in bring free traffic)

Special Assessments generally spook buyers so removing this potential objection is always a higher priority than trying to optimize for purchase price / payment.

This usually is easier to capture return guests to book with you as opposed to competing with the top companies and the million dollar SEO budgets that they use to come up under and search you could think of for vacation rentals.

I would focus on buying a handful of high quality B properties (for the optimal combination of cash flow and capital preservation/ possible appreciation) with low turnover and low maintenance costs rather than many lower-tier properties that will likely bring more issues, especially if you have to deal with Section 8 housing authority bureaucracy. 

If it drops it to a number below the ROI you could get elsewhere... why not sell it and take the profit + reinvest in optimal returns?

If so, what areas are optimal for a good cash flowing rental (minumum vacancy rates)?

You can find calculators for this using YOUR income / expenses by searching "Equity Optimization" or "Equity Advantage" input YOUR numbers and get a result.

Get a good web service like investor carrot and either hire someone to optimize it or learn it yourself lile I did. 

I mean negative money is not optimal

Aside from the management, there are many optimizations that are probably lacking which is why one property is drastically underperforming compared to another.