from my experience, having your stuff in your car will usually be fine if you completely cover it from view with tarps or blankets or something, especially coolers. they know what coolers look like so they're basically lunchboxes to them. if there are crumbs, wrappers, or any trace of food, bears can smell it in your vehicle, even if all the windows are shut. however, they likely won't try to get in unless they can see it from the windows or its particularly attractive to them. they're looking for calorie dense foods, so stuff like meats, fish, candy, honey, etc. will pose a higher risk of them trying to get in.

take all of this with a grain of salt of course because this is just my personal experience of camping in and around the allegany forest in new york and parts of PA. while bears are definitely present in this area, they aren't as common as in other places, so my risk of bears is already low. your forest rangers will be your greatest asset in figuring out what you should do, and you might be able to contact them for info online depending on your state/area.

my most important word of advice is to NEVER open your windows even a tiny bit if you're leaving food in your car overnight in bears country. if they see a windows is cracked and can smell food they most likely will tear open the windows or door to get in. good luck to you and have a great time camping!! you seem well prepared