my last comment to the OP... if you really want to have a good experience in the outdoors with your daughters... pick another month to go... Fall or even early winter. You have the right idea picking MC Nat. Park, and car camping... But sleeping in a tent this time of year is like being in a greenhouse... It's hot at night and "great ventilation" don't do squat when nightly temps might be in the 80's... Cave temps are the same all year round so a tour, if interested, isn't effected....... have fun.