Last year I needed around a 1000 miles to maintain my Silver with NW. Flew a $120 route, ORD-BWI-ORD, on a Saturday, stayed overnight in an airport hotel, returned the next day after, met my family at ORD and we all flew the same route to spend the holidays with my in-laws in Northern Virginia. The unplanned reward - I flew to KUL last March on J class which qualified for a double miles promotion, plus 50% J class bonus plus 50% Silver elite bonus plus 10,000 promotion bonus for flying J class totalling 68,500 miles.
This trip was sponsored by an international organization who prepaid the airfare but their travel agency failed to request the ConnectFirst option. I could have booked the flight myself in the Web for $2000 less, received 5000 online bonus and flew FC. Oh well, I can't complain much for this convergence of these opportunities.