Southwest is getting ready to change their credit card program (I think it goes into effect in March). Right now, if you get a free ticket you can only use it to book flights that have open seats for the reward program. So even if there are open seats on the flight, you might not be able to book it with your free ticket. Unfortunately, you can't see the webpage that has the available reward seats unless you already have the credit card.
We got the card this spring and ran into some problems using 4 free tickets for our summer trip. We had to play around with dates to get what we wanted. Anything near a holdiay was blacked out. And we were booking for a June trip way back in December.
However, under the new program you can book a seat for free on ANY flight that has an open seat. Plus the points you earn won't expire. So I think it might be a good idea to wait to book any free flights until the new rules come out, since you'll be much more likely to get what you want. Good luck!
