My new-Y7 ds is cycling off to the station every morning to catch the train to school (a short ride across the park). He can ride with his incredibly heavy backpack of books on, but can't figure out how to manage when he has his p.e. kit or guitar as well. is there a safe way to do it? should I get him a basket, a rack on the back, panniers? A lot of those things seem to be detachable but he won't want another thing to carry onto the train, nor do we want it disappearing off the bike while it's outside the station. Any suggestions?