Well, in the past you could get the absolute best fare for SWA right upon release of the rates. This is really no longer the case. I bought round-trip for this November back when the dates opened up back in May. We ended up booking and it costed $340 round trip, which was rather high, but I got the flights I wanted.
Later, they had a big fare sale and the prices dropped. I got $100 worth of credits for those flights - so subsquently the round trip price got as low as $240 round trip.
Since you are flying around a holiday week, it is quite possible that fare may not drop. If I were you, I would look at the price when they publish the fares, and decide whether it is a rate you are willing to pay. If it seems way too high, you could wait a little while, but I would watch it closely. If you are going to be flying again on SWA within less than a year of your ticket purchase date, you could always buy the ticket, then take the credits. It's really a tricky game to play - but at least with SWA you DO get the opportunity to get credits.