As has been said take and wear your life jackets. Take and have easily accessible a serviceable liferaft.
I know somebody that ditched a PA28 successfully was wearing a lifejacket but the liferaft failed to inflate. He was rescued after less than 30 minutes but the cold was apparently awful.
A rare event but as in all things flying preparation is all.
I also agree that good planning for an alternate is a wise precaution.
With all that in mind have a good trip, it is well worth the effort.