Id say make sure you contact your boater ahead of time. I.E: No need to bring 2 boxes of DD cranks and jerkbaits if your flipping weeds. I usually just do 3-4 3700 boxes. 1 for cranks in the colors I fish at said lake, 1 for soft plastics, 1 for jigs, 1 for terminal tackle. As far as rain gear I have a compact set that rolls up into little pouches which I throw in my lunch box or I'm wearing and wouldnt make a difference. Culls go in a pouch on my bag and nail clippers in my pocket. Sunglasses on my face. My problem used to be bringing 7-8 rods now I just keep it at 5 every trip regardless.
***EDIT Also depending on how friendly the guy is I'm paired with I ask in advance if I can use cargo space behind passenger seat. Most Skeeters, Rangers etc its more than big enough to house a tackle bag and lunch bag/box.