The problem of acres of cloth and car seats is easily solved. Drive naked. But seriously, I have found that 'right hand under' getting in, followed by a sort of 'rise and smooth' two handed action gets everything arranged in a satisfactory manner. Getting out is not a modesty problem either if one simply moves the outboard leg first, then quickly pushes down on the center of the apron.

But a word to the wise: never have your car seats done in silk if you want to ride in a wool kilt.