I work primarily on the south side of the city, but we can do work throughout the city and also the northwest Indiana area, (travel will depend on the size of the job).

It's not a one-size-fits-all situation.  

I would think 5k or 10k would be plenty, though it will depend on house size, age of roof, windows, sewer, AC, Furnace, electrical, plumbing. 

We just took off the old sheet material and underlayment and even after more than 15 years there was only one area about 1 foot square in size that had some wood rotting.  

I build new construction duplexs, althought at a much lower size then yours (1800-2450ft2).  

So, screening too stringently in some of those lower income neighborhoods could substantially reduce the size of the tenant pool for you, to the point where you might be searching for the proverbial needle in the haystack.

Rental agreements, background checks etc. would be no less stringent than any other tenant who may be full-time employed (someone mentioned the risk of a student dropping out).  

Currently I have been dumping 13% of my work income (10% from me and 3% from employer) into my 401k. 

The location would probably be on the bottom of the list of importance, you need to look at other factors such as experience, quality for client service, etc.Second, as a self-employed real estate professional you should consider self-directed Solo 401k, which is much more superior to an IRA for several major reasons, you can read more on this blog post: http://www.biggerpockets.com/blogs/2810/blog_posts...

Amstar Construction Management Group (2013- Present) is a custom home builder and construction management consulting firm; we employ and manage the skills set of other professionals: certified contractors, specialty trade contractors, and individuals.