Short-term unit + long-term units + owner-unit = Success?

[Lars Olsen]

Hi All, 

I did search the forum in case someone had asked before me, but to no avail. However I am new to BP so please bare with me if I messed up. 

Background for my question: My wife and I are looking to buy our first live-in investment property some time the coming 12 months in Chicago were we both live and work. Ideally a 4-flat with garage. My parents are from and live in Norway, but visits regularly and I'd like for them to have their "own place" here. Needless to say it would be a little extravagant if their place would be empty 11 months or so out of the year. Therefore I was thinking to operate 1 of the 3 rental units as a vacation home (inspired by last week's amazing podcast) aiming to keep the unit occupied enough to generate a similar or even higher income to the other two long-term units.

Does anyone here have, or have had a similar set-up, and would like to share their experiences with me? Any obvious pitfalls I need to be aware of, in general and for the Chicago market specifically? 

Any input would be valued, be that tips on landlording or the financial aspect of an investment of this nature. 

Lars