I have been working remotely for the last year after working in an office for ~14 years.
The largest potential issue that I have run into is is communication and how it is handled.
The most important thing I would ask would be how many of the people on the team you deal directly with are remote. That will give a pretty good gauge on what it will be like.
I would also ask why they chose to open up remote positions. Is it a last resort to get people hired or is it because they just care about the quality of the hires. You may or may not get an honest answer here, but I would ask it any way.
The other I would ask is what is the primary means of communication in the company. If they say "Campfire", "Flowdock" or something along those lines - ask how many rooms they have and how active they are. The key here is asynchronous communication, with remote positions come different schedules, removing the need for instantaneous response is nice.
Along those lines I would ask about hours that people work, are there core hours or is it 8-5 Pacific time, etc. If there is a rigid schedule, that is a bit of a red flag for me.
I would also ask how often the team gets together, this should be a priority and I think once a quarter minimum would be a good time frame.
You mentioned a devops role, so this might not be as big of a thing for you, but I like to see them using pull requests (or similar methodology) for feature merging. In my experience thus far, those have really helped keeping team members up to speed. That isn't a deal breaker, but a good thing if I see it.