If you register for the Southwest Visa, you can immediately become a Freedom Member with a numbered account. Then by booking through the internet, you get double credits. You get credit for one round trip just by using the credit card once. You can earn a credit for each car rental with Alamo, Budget and Hertz. Via this strategy, with a car rental for each trip, you could have a free ticket with only 3 flights. With many of their flights costing about $80 round trip, that's
pretty reasonable. You can use the free ticket to any destination, even if there's not a flight combination listed in their schedule.