My hubby owns a PT cruiser. We just returned from a 4 day road trip to PA and had the car loaded! Suitcase (large), 2 strollers (one had to fit between kids car seats in back), duffle bag, cooler (collapsible), lots of kid stuff, grocery bags, etc. It can hold a lot. It would also depend on how many people were traveling with you. You can put one side of the back seat down flat, or folded up against front seats. There is also a tray that acts as a privacy screen, or if you need the room you can lay that flat too.
By the way, who is EA that is renting them? We are going down in December and I might like to rent one since I can't drive his!!!!! I do all the driving when we're there anyway and it is such a cool car.