Guerrilla grow? I'd just say multiple bagging would be suffice. How far you driving? Haha. Not saying anything sure fire, but if you're not talking long haul transport, anything somewhat air tight should be fine. Just dont drive next to a cop car with a K9 in the back too close..... Not a joke, there was a bust near me on the freeway that the K9 was going ape****. Box truck next to it got pulled over under suspicion with 600 lbs if I remember right.
Put them in a cooler that is air tight. You may want to put them in a couple of plastic bags first. Cut the individual branches off and transport as little amount of "trash" (throwaway stuff) as you can.