Well, 3 at once may be a problem.
But when Puff and I drive on trips, we're mainly on Interstates and stop every 2 hours at comfort areas for 10-15 minutes of exercise (slinging a Training Dummy for her to fetch). That worked very well for both of us on two separate 3,000 mile trips, one KS → VT → KS and another KS → OR → KS.
