I have a walk for breast cancer tomorrow and I've raised over $2500 but should I walk the mile or 2.5 miles? :)
Sure, go the extra mile and a half - you'll feel great about yourself afterwards, even if you are completely sweaty!!!!!!!! anyway youll burn a few extra calories!! have fun!
You have done the most crucial part. The distance you will walk is not of much important as you have already met the objective of the walk. If you can, then walk the longer distance.