It's important not to ruin other guests' fun at a bachelor party, so avoid doing something that will spoil the mood. For example, don't get insanely wasted and do something you'll regret later.
You should also keep in mind what the guest of honor dislikes. For example, don't invite people the groom can't stand or plan an activity you know he won't enjoy.
And most importantly, don't let the groom pay! He already has to deal with the wedding expenses and needs to relax with his buddies for the bachelor party. So go ahead and book a brewery tour or yacht party for his celebration in San Diego.