Isaac , this is a very ambitious project my friend.I would start with Bildwise ,they have extensive experience in this market,and contractors they use all the time,which gives them consistency.They can probably ball park it for you first and then do a detailed sow if you choose .Disclaimer :I have no affiliation with BildwisePlease keep us in the loop with progress 

What if it needs a new roof but inside if mostly ok?

I assume it's just the bigger stuff and single family homes (electrical, roofing, etc) but just want to make sure as I want everything done the right way (not always common here in Miami.)

but if you are starting out its going to be 4 and 14  4 nd 12 that kind of thing until you get some projects in your experience bucket. 

In 4 years I have projected that my strategy has saved me $13-$15K in vacancy and lease up fees.  

How old is the home- are you incorporating longer term rehabs- like roof, plumbing, windows, electrical and Heating/ & AC?  

The important thing is to find the balance that works for you.Finishing up “Later”Don’t be fooled: if you start a project or task, you need to see it through.

Check on the foundation, roof, plumbing, and electrical.

Replace a roof and you will most-likely have zero profit for the year in actual dollars.  

Do 3, 5 & 10 year projections.