Vacation outfit

We're currently counting down the days to our vacation in San Diego and I'm frantically trying to decide what to wear! I have several dresses that MIGHT work but they just don't seem perfect and of course Dominic has no idea why it really matters. I've explained to him that men have a wedding 'suit' that works for all, but he just doesn't get it. At this point I'm going with my brown dress from the rehearsal dinner but I thought brightening it up for spring might be nice and a cardigan might come in handy for the outdoor ceremony...what do you think of this cashmere number from Jcrew?? As I've said to Dominic, you can NEVER go wrong with cashmere.