In Vermont there are lots of ticks these years, many people I know have had Lyme including my husband and dog. I've so far escaped. We've been using cedar oil -- Tickshield for several years. I spray myself whenever I'm in the woods and haven't had a tick yet. Dogs who get sprayed don't seem to get any ticks. This was introduced to me by a friend whose daughter went to a wilderness camp in NH where ticks abound. The kids were required to bring this with them -- none of them got ticks. That convinced me, and we've had similar good luck (except when it is forgotten).
So, just another option for you.
Best, Lindy