My parents had me out camping when I was 6 months.
We took our oldest out camping at 5 months.
Here is a pic of the family, 5yo and my 16 month old this year at 4 Corners.
The key is not to drive all day, stop at the city park and have lunch and have camp setup by 6p. That way they can get out and explore and you can take a nap if need be.