Lvmike: I have used and recommend the large garden size plastic bag and your favorite flea and tick spray liberally applied outside the vehicle and then tied shut before placing in the bed of my VarmintMobile.
The fleas that don't die quickly will probably not be gettin out of that situation!
Could you tie said bag to the roof of your 4Runner for about two more stands/set-ups before placing the bag and contents inside your rig?
Best of luck to ya.
Hold into the wind
VarmintGuy
I hunt from a Subaru at times and the above is what I do. Shoot them and put them in a bag with a liberal amount of Raid. Leave them outside the vehicle (on the roof) for the next stand or two. Then I'll pull them off the roof and skin them on a fence post. Place the pelt in another garbage bag with another shot of Raid (to be safe) and then into a cooler or box inside the car. No fleas, bugs or blood inside the car yet.
