Hey, 

So I decided to run with teaching her the 'base' of the Water Gun Technique, Spirit Gun of course, and am hoping this poses as a suitable challenge for her. To keep pace with someone easily faster than her, focus her chakra to the tip of her finger at a suitable amount, AND to take a shot at him is adding pressure from the start. She has five minutes each time before he allows her to catch up, and she must start from the beginning after each failure so she has an easier time. Kakashi hasn't said it, but he WILL dodge her shots. This can go on until Sakura and Kakashi take a break before they hit the rest stop for the evening and eat lunch.