For starters, I'll say HYOH. Our family of 5 hikes about 500 miles a year through prime tick country and prime tick time. Since we are working to avoid as many chemicals in our food and lifestyle as possible, we prefer not to slather ourselves in DEET or Permethrin. We also don't prefer to wear long sleeves and tuck pants into our socks when it's 85 degrees out in the middle of the summer. So those aren't options for us.
One important tidbit to know about Lyme's disease is that, per the CDC (
http://www.cdc.gov/lyme/faq/index.html) the tick must remain attached for longer than 24 hours, and that's for the black-legged ticks (deer ticks) only. Thus, we have used a nightly check routine as our primary line of defense. Of course, we also see them earlier in the day and stop to remove them then. Though two of our four children have been infected with Lyme's from daily life on the farm, none of us have been infected while on the trail. YMMV