Definitely ask. They may be okay with a night but there have been local sqauters that ruin it.. There are two rest areas south of Ontario. You can stay up to 12 hours. One is coming from Ontario and the other from Idaho. Also Pilot truck stop and Loves will let you stay a night.
I travel a lot and even if somebody says yes its ok I always go in and ask the manager or assistant manager if it's okay unless the parking lots full of trailers :)
I don't know their official policy, but many do stay overnight for one-three days.
There's an app thru Play Store that shows you all the Walmarts in the US that allow overnight parking. It's gotten pretty good reviews
Yes you have like up to seven days.
Technically no but one night nobody would bother you
Thanks! Your answer is awaiting moderation.