I've spend a lot of time in tick country...I've been covered in them 3-4 time (hundreds of babies, nymphs, adults, 3 different species) since I like to hike where there are no trails (especially in FL, though have gotten them bad in AR and MI as well).
DEET does not repel ticks. Not if they are hungry enough...not even 98% stuff that turns your skin red. In fact, nothing repels hungry ticks except layers of clothing they can't go through (the babies can go through the stitching in socks). I've read stuff to the contrary, but I've gotten covered with ticks with many sprays on my skin/clothing...A hungry tick doesn't give a ****.
Wear light clothing and BRIEFS with elastic on both legs (usually enough to stop nymphs/adults from going any further). A couple tick facts to remember as well...It usually takes them a while to find a spot to bite. Feel/see them and get rid of them before they have a chance. Only females bite, though you may have males on you if you have females on you (just trying to get some action).
Deer tick carry the most serious diseases. Fortunately they are slow to attach, and need a minimum of 24-48 hrs of attachment to transmit disease. The babies, which are almost impossible to defense against, luckily do not carry disease. Ticks must get disease from other mammals (usually rodents). This is why in areas like FL, where ticks bite lizards/snakes, there is little to no Lyme disease.