One trip I thought would be fun would be starting at Climber's Bivouac at the base of Mt. St. Helens then loop around the Mountain, up to Rainier, around it on the Wonderland trail then over to Goat Rocks Wilderness then back to Mt. St. Helens. Could definitely be done in a week, but would need long/hard days....three different and amazingly beautiful landscapes.
(I don't know that Lost Coast would occupy you for 7 days...just my 2 cents).