I don't think it is.
The forces required to pull the Earth out of its orbit would be tremendously powerful, and would cause cataclysms on the planet which would wipe out even the best prepared colonies.
Underground bunkers would probably be crushed as the Earth experiences massive earthquakes, volcanic eruptions, etc. (this is actually a big problem of ours regarding the storage of nuclear waste: there are very few places - if any - where we might be certain that our dump sites will be able to sit undisturbed for 50K+ years)
Furthermore, consider that once floating in the depths of inter-solar system space the Earth will get incredibly cold very, very quickly. You can pretty much forget about doing anything on the planet's surface.
We will no longer get as much light as we did before, so that won't be a very good method to generate power. Geothermal power may sustain you for a while, but the depth at which you might be able to tap into that will probably change dramatically, so unless you are prepared to drill even further down you will be in trouble.
If your people somehow managed to survive the initial catastrophes, they would be stuck in a bunker which would become their tomb sooner rather than later.