For one thing I have yet to see a dirt bike that would carry 8 people.
And I would not leave my family behind.
You will do as you like of course.
Well, in your case you would need at least four dirtbikes then.
Unless you want to be trapped on the interstate with thousands of others in you Ford Excursion..
you could always try the back roads.....like everybody else is thinking.
Better be armed..