We bought a New Beetle for our daughter. While it is surprisingly roomy for a small car, I find it to be a bit low to the ground, and I’m just 5’5" or so. Out PT Cruiser was a good height for entrance/egress, but I don’t think it’ll accommodate much girth.
Take a look at the Honda Element. Yes, it’s a box on wheels. But it’s got lots of head room, more shoulder room then most, it’s tall enough that you don’t step up to get out of it, and it’s got suicide doors in the back. This allows you to open both front and back door if you need the extra space, with no support inbetween.