Alaska DOT&PF's website has a page reporting updates on how the earthquake has and hasn't affected major roads:
http://dot.alaska.gov/earthquake2018/Main items:
-- Seward Highway (AK 1 south of Anchorage) briefly closed several miles south of Anchorage due to rockslide, though it has since reopened. No mention of detour, so for a time there may have been no alternate route between Anchorage and the Kenai Peninsula
-- Glenn Highway freeway (AK 1 northeast of Anchorage) closed in at least one direction at Eagle River, detour available on local roads in Eagle River
-- One ramp of Glenn (AK 1)/Parks (AK 3) interchange closed, with detour to Palmer; other major damage to interchange
Highways more distant from Anchorage seem to be largely unaffected.
Some damage to Anchorage International Airport and closures of some roads to airport, but a reduced schedule of incoming and outgoing flights has resumed.