You might want to check into lightweight Snake Guards (http://www.snakeguards.com/snakeguards.htm). I would suspect that most bites to the legs would be below the knee. Don't wear tight pants in snake country. I think the second most 'popular' place for snakebites is on the hands. Use a stick for poking areas you can't see.

Antivenin is used very carefully by doctors, almost always in hospitals. Before they give you any, they test you to see if you're allergic. If you gave it to yourself and went into anaphalatic shock, you wouldn't be able/wouldn't have handy the airway, oxygen, epinephrine and cortisone required to deal with it. Besides, it needs to be refrigerated, and a serious bite could require from 10 to 18 vials of the stuff, at a cost of $250-350 per vial.

OTOH, a set of Snake Guards cost $58 + shipping. Hmmm, a tough decision.

Sue