sway bars/ yes or no

My wife and I just purchased a 2004 Jay Flight, 27 foot travel trailer. She also just purchased a Nissan Titan, that we intend on towing the trailer with. We purchased a wd hitch and have made two small trips in the texas hill country with no problems. The question is this. We are plannining a trip from south texas to california, via colorado and new mexico. should we purchase sway bars for this or not. if so what would you reccommend. thanks