I know you've changed your plans but I do a lot of split stays with a car. I do it one of two ways, depending on my mood, with variations on those. Way #1: I get up fairly early even on vacation so I get up, eat breakfast, put everything in my car and head over to resort #2. I'm usually there between 7 and 8 am so obviously 99% of the time my room is not ready. Variation #1 for this way, I leave my luggage in my car, go check in just to let them know I'm there and head off to a park. Variation #2 for Way #1, I take my luggage with me when I check in and leave it with bell services and head off to a park. Sometimes I'll pick it up myself from bell services and take it to the room, sometimes I'll call them when I get to the room and have them drop it off.
Way #2: I still get up early and have breakfast, take my luggage to my car and leave it at resort #1. When I'm done with the park, I ride the bus back to resort #1 and head off to resort #2 (95% of the time this is after I've gotten a room ready text).
I always park hop and always go to the resort at some point in the day to swim or rest so Way #2 is just my break in the day.
I don't have anything with me that needs a fridge, sometimes I might have some fruit or cheese I snacked on during the drive down but that just goes in a small cooler so is fine in the car.