Can I sleep in my car at this plaza?

I have, there is plenty of parking out of the way, truckers do it all the time.

Yes

Plenty of room, ok to stay for a while

Yepper

Yes. I layover often there.

Yes. It's a layover area and a lot of truckers sleep there

Thank you. Is there a rest area on I 35 S closer to KS?

I did...im not sure if your supposed too but no one bothered me.

Yes you can.