A lot of good answers below. I cycle 5 miles either way each day and use the 'spare clothes routine' left at work. Each day I have something new to wear, just one item, so clothes are continually being transported back and forth. The shoes always stay there. Get a good back pack, they are light and should not make you sweat if they are the type that sit off your back. I also have double cycling gear - 2 shorts, 2 leg warmers for winter, 2 socks etc, just in case it rains and one lot doesn't dry by coming home time. And who cares about getting wet on the home trip anyway? I would also seriously ask at work about somewhere to change; they want a healthy and active workforce, don't they? Tell the others in the office what you want and get their support. I've also been given a key to a small boiler room where I also leave the bike.