Zimmermann's a registered Democrat
He was also born in 1983, so he won't be eligible to run for the Presidency until 2020. He will get his first shot at a Senate seat if he wants to run against Rubio/for the open seat (presumably as a Democrat) in 2016. If he wants to run for the House, he can do that next cycle, though it's unclear which district he's in -- whether he can be a sacrificial lamb against John Mica or hopelessly challenge Corrine Brown in the primary. (Though Zimmermann's been eligible to run for the House starting in 2008.)
And, yeah, seriously speaking Paul is a pretty good fit for Alaska Republican types.