Can you park overnight

Yes

Yes you can

I used to see trucks parked on the east side of the parking lot, but since the truck stop opened across the street, trucks seem to be parking there now.

There are a bunch of signs that say you can't, but no one enforces it. Pilot is right across the street and they allow overnight parking.

I have had to in my car before and no troubles and I know the OTR drivers can and do in the back of the lot.