A lot of the articles i read online made it seem as simple as, if you have leftover, use it! 

I would recommend just starting simple and not over thinking your strategy. 

I think 1031 exchange might be in my future, or an increase in rent.

With the flood insurance cost, this unit will be neg cash flow unless I increase the equity in the unit which brings it down to less than 5% cash on cash.

My question is: is it possible to raise the rent up to market rates if a new tenant is placed, or does the unit need significant upgrades to justify such an increase?

I think would like to renew, but they've occupied the property for some time and the rents in the area have probably increased.

The key was SEO, simple processes, very targeted and directed keyword marketing, automated payment and enforcement.

I want to keep it simple.  

I have about 150K to invest with the same amount in reserves (but could be used to increase my position).

A LLC will not provide any better protection at your point in investing and will only increase your operating costs and make it more difficult to get financing going forward.Insurance is the real protection, LLC is more for psychological protection.