Sounds like you no longer need pull ups, but FWIW we found the mother ease one size made decent pull ups, we could fasten them loose enough on DD that she could pull them up and down, plus of course easy unsnapping if needed. We used them without a cover so still needed a change of clothes but no puddle to deal with. We also had some pocket trainers which we used overnight, though again as DD was skinny we found pretty much any pocket we could fasten so she could pull it up & down. I think they might have been these, http://www.happyheiny.com/our-products/training-pants
I did keep a folded flat in the car seat for a while, I know you are not supposed to put anything in the car seat but felt since the week before they were wearing it I was happy.