I'm not sure where you're staying, but the preferred room was worth it for us at CBR last year. I know you can request rooms there that are just over the bridge from Port Royale, but at least with preferred we were guaranteed a room in Martinique or Trinidad North, the two groups of buildings closet to OPR. For us it made a difference because our kids were 4 and 2 and we had lots of walking at the parks ahead of us. I'd say if you aren't planning on using the food court a lot then it probably doesn't really matter that much at the mods since there are several bus stops around each of them.