I think Air Canada has seasonal (summer) service to Anchorage from Vancouver. So it should be possible to fly AC or UA from EWR to YVR thence to ANC (and back).

It looks like AC operates daily, with a flight leaving YVR at 11:50 a.m. (or thereabouts). I don't know the minimum connecting time in YVR, but the early morning AC departures from EWR look like they might connect OK in YVR. I'm not sure what happens when you're on a U.S.-originating flight connecting at a U.S. preclearance airport (YVR) in Canada for another U.S.-bound flight. I think you still have to go through U.S. customs and immigration in YVR, so that might violate minimum connecting time there.

The return flight leaves ANC at 2:50 p.m. or 3:00 p.m. You'd definitely have to overnight in YVR on the return with the present schedule.