Maybe from Paulina Peak. Just a few feet under 8,000. You can see Idaho and California and Nevada and Washington from there.
Nope, not from Bachelor either. Here's a link to a calculator that computes distance you can see to the horizon based on altitude.
http://www.ringbell.co.uk/info/hdist.htm
Paulina Peak at 8,000 feet would only give you a distance to the horizon of about 110 miles and it's about 230 miles to the coast from there. Mt. Hood is about 11,200 feet in elevation, would give a horizon distance of 130 miles and the coast would be about 160 miles away. Mary's Peak is 4,098 feet in elevation, which would give a horizon distance of about 78 miles and the coast is only about 25 miles away. The location would have to be in the Coast Range. The five highest points in the Coast Range are:
Marys Peak, 4,101 feet
Rogers Peak, 3,706 feet
Grass Mountain, 3,615 feet
Laurel Mountain, 3,592 feet
Bone Mountain, 3,547 feet
The farthest inland of those points is Bone Mountain, which is about 31 miles from the coast. I'd go with that as the answer to this question.