I would use a very wide collar with an O ring run through it and the tie out attached to the floating O ring as opposed to the fixed D ring built into the collar. This way if/when she hits the end of the lead the wider collar will protect her neck a little and the O ring is less likely to break and does not always stress the same point on the collar.
I know Jocoyn has mentioned about teaching her dog where the end of the line is, she probably has a more thorough method but I always take my dogs to the end of their tie out so they know how far it goes. They usually don't test it too much. I tie mine out when we are camping too but they are quite respectful of their tie outs.
If you feel your dog is going to hit the end a lot I would be careful about what you use, you don't realize how important good quality equipment is until they break a poor set up.
Eli - Hellwigg's Freedom in Stride RN RA SCRB1 CGN TEC
Cajun - Hellwigg`s Hot for Karma CGN TT UCC
Evie - border collie mutt CGN
Sweetie - APBT CGN