When I took my dog out in the tick-infested southern Illinois woodland in late summer, I sprayed each of his legs with CedarCide. This stuff is basically texas cedar oil and smells like, well, cedar. I sprayed it on my legs as well. Neither of us picked up a tick but multiple others in our party did.
Cedar oil is toxic to cats, but it seems safe for dogs. I didn't put tons of it on him, just on his legs and maybe a quick swipe of his belly.
A couple of years ago I used it on the hotel mattresses at Disney World in Florida after I'd heard about the trouble with bed bugs they were having (and I'd sent away one
mattress for having suspicious debris on it). It's not completely non-toxic, but I'd call it less toxic. I bought a gallon of the stuff and I've used it for protecting wool clothes as well. Better than moth balls!