I have commuted to work by bike for years. I have ridden the fast road bike the whole distance on main roads, taken the MUP and also done the bike/train or bike/bus combo. I live in a hilly area in the southern U.S. and my commute is 20 miles one way or 32 kilometers. It can get quite hot, humidity is a factor as is rain most of the year. To ride the whole distance, either on the fast bike via main roads or relaxed bike on MUP, I need to be able to shower when I get in. For me the bike / train combo works best.