Because my DIT is low, maybe Case 2 for fourplex is my preferred loan type than Case 1 if I want to invest locally.

Welcome to BiggerPockets Melanie and best of luck investing!

Where you invest depends on your ability to do a market analysis. 

My wife and I have jumped in and invested in two separate STR properties in the Blue Ridge area. 

We also tell them that we charge $25 per hole for TV mounts, shelves etc I think that $10 up-front investment has reduced the number of issues by probably 80%.Our walls are textured (sand textured in Milwaukee, orange peel textured in the western suburbs - yes, there is an actual dividing line), so we try to avoid the usual palm-sized patch and fill only the hole without making it bigger, so we can get away without texturing.

Can anyone recommend a calculator to assess STR investments ?

I''ve only heard of ones existing who work on large constructions projects, not small single family home investment properties.City inspectors will inspect as part of the permit process.

You're in the right place to learn about real estate investing.

What does a cash positive investment mean to you? 

Using a calculator to project what a syndicated investment "opportunity" might do is akin to masturbation.