Personally I choose to keep the "tools" in a toolbox in the bed, but my Dakota has a locking hard cover on the bed, so it is an easy choice to make.
In the cab, I would keep the length of the tool under the legal definition that makes it a weapon.
As far as your passengers are concerned, if you claim the knife as yours, they should not have a problem unless they do something stupid that makes them appear to be a threat, But IANAL