Yes, stronger hold gel. If you are traveling before late May/June, the air will probably be pretty dry (and probably windy at times) as you go North and you won't have the volume and curl boost from humidity (I'm almost halfway between you and Montana and the dewpoint here was 10°F today). You may want to be sure to use a leave-in and use a stronger-hold gel to keep your hair in place. Wavy curls tend to wilt in very low humidity. Humectants can sometimes backfire on you and give you more frizz when the air is dry or make your hair feel day - YMMV.
Husband always reminds me when I'm packing - there are always Walgreens or Wal-Marts or Targets or Shopkos and well-stocked grocery stores in medium-sized towns if you need something.
If your hair is long enough, bring ponytail holders and a headband or hairpins or barrettes in case you get too much wind or just want your hair out of your face. If you're camping - some nights are just too cold for a shower and some mornings are just too rainy or windy to bother fixing your hair.