Typical high country season applies, most likely June to October.
This is a 4x4 road (open to vehicles). Higher-clearance 4x4s can drive all the way to the top—unless you're sure about your vehicle's off-road capabilities, leave it at the lower trailhead.
From Alpine, this road climbs steadily on a sidehill before entering a drainage. It's rough at times but not unmanageable. After Forest Road #278B (Baldwin Lake) splits off to the right, the going gets steeper as the road ascends the western flank of Antero.
There are several small parking areas at the bottom of Forest Road #277, along County Road 162 (Chalk Creek Dr.)
at the upper entrance to the town of Alpine. The trail is entirely 4x4 road that can be steep and rough at times, more so near the bottom than the top. It begins at a junction about 2.6 miles up Forest Road #277 (stay right). Left goes up to the summit of Mount Antero. Overall, this isn't a must-do, but if you're in the area and looking for a good trail for an out-and-back, up-and-down route, this takes you up to a solid high country viewpoint at the bottom of the east side of Grizzly Mountain before enjoying a ripping descent down a 4x4 road.