Being a resident near DTW, CLE is a savior for those needing mileage runs. The maximum miles you can rack up is CLE-IAH-SEA-IAH-SEA from UA, totaling 5930 miles. It's a painful and torturous run with red eye RT, not ideal if you can't take days off work (be ready to work upon CLE arrival).
If you're willing to spend a night in Seattle (highly recommended for hanging around fish market and riding the ferries), currently the following Sat departures are available - April 13th ($278) CLE-EWR-SEA-EWR-CLE netting 5610 miles, May 4th ($275) CLE-IAH-SEA-IAH-CLE netting 5930 miles and April 27th ($248) CLE-IAD-SEA-EWR-CLE netting 5399 miles, beware some FFPs do not earn miles on N fares.
Another semi-MR option is CLE-SMF (I visit relatives for one day) starting Sat, and you get near 5000 miles for each run, most of those fares are available in Aug and Sept.
Last edited by vincewy; Feb 24, 13 at 1:37 pm.