The water bills are a big cost to me.

I looked into Google PPC ads and Performance max ads, but after spending hours creating my ad, it was going to cost about $65/day to be competitive in my area. 

It also is worth approximately $140k more than my property is currently worth.My question: when evaluating renovations, is the math as simple as (Additional rent expected per month due to renovation * 12 months/yr)/total cost of renovation = ROI.

Age of construction may not be a huge issue if it has good bones and can benefit from a fairly cost efficient "In & Out" remodel.What is stopping you down payment?

If you're going to flip, it could work, but you would need to analyze the properly for that approach -- which would included getting detailed and accurate estimate on repair costs. 

Partner Driven financed the N Deerview Dr deal using its own capital, covering the $268,750 purchase price and $60,000 in renovation costs.

Rates will be more volatile and going into a cycle of rate easing by the FED's these rates are set to drop soon which could cost you in interest earnings. 

If they were the right land/building ratio and made sense to do a cost seg/bonus depreciation, could I potentially offset my entire W2 salary?

Selling costs will consume about 50%.  

Initially wanted to hold forever but with insurance costs rising/property taxes going up/threats of Hurricanes destroying home, considering cashing out.