As mentioned, boiling too long won't decrease the sugar content of your beer. In fact, it will increase it. It can also increase kettle carmelization, which is why certain beers like scotch ales can have boil times of 2 or 3 hours. Racking to secondary early or late also shouldn't be much of a problem. If early, you should still have enough yeast to continue to ferment, though you might not have as many solids settled out of the beer so you might be a bit cloudier. Too long only becomes an issue if it is months too long and you suffer from off flavors due to the yeast breaking down. I'd recommend http://homebrew.stackexchange.com/ as a great place to learn and ask questions about brewing.