RTMCC, I haven't jumpseated in a while (been furloughed; now doing AF Reserve stuff), but my kids and -ex live in DEN, so I'm familiar with getting in & out of there.
I don't believe in commuting, but it's definitely do-able. I'd favor MDW over OAK due to the larger number of available seats in close proximity.
With OAK, you've got SFO as a backup airport. Having flown out of SFO, I can tell you that's one heckuva crapshoot; a little bit of fog & you're looking at big delays and cancellations.
If you choose MDW, you can use ORD, and use STL, MKC, MSP, and DTW as backups for connecting flights. If you get to one of the alternate cities, you can always rent a car one way to make sure that you get there on time (been there, done that).
And don't forget the ID90s; I'd have one available for every airline that goes to MDW/ORD. They're refundable if you don't use them.
When I got hired by my first airline (a 121 sched charter), I had to do a double commute. It was difficult, but due to proper planning, I was never late.
Commuting will likely not be a lifetime choice for you, unless you need more time away from the family.
Good luck to you and have a great career.