I hear you on the family dinners... we eat together once or twice per week at best. I miss that!
For snacks, DS has a protein bar (usually the Nature Valley brand with peanuts and chocolate) on the way to practice (we go straight from school). Then during the 3- and 4-hour practices, he has a Luna protein bar, some sort of protein/breakfast-type shake, and a piece of fruit. That seems to be enough to get him through.
We probably overdo it on the protein bars, but he is picky and that is one thing I can count on him to eat. I look for ones with low sugar.
We also do cheese sticks, nuts, applesauce, grapes, and other small, portable snacks. Between practices and pickiness, it's tough to get him to eat a full meal, so I just stock the house with healthy snack options. Looking for other ideas!