I do a lot of fieldwork that involves bushwhacking through dense areas with lots of ticks and prometherin is a game changer!  It's an insecticide, so some people don't like it, but I did a bunch of research and decided it seemed okay.  In my mind it is much better than lymes disease!  You treat your clothing (I usually only do my pants and the top of my socks that are exposed to the air when I tuck them into my pants) and I have literally seen ticks die crawling up my pants.