How hard to cycle 150 miles in 2 days?

I know that people in Britain often use stones as a measure of weight, but you also use pounds as many people outside Britain do. To answer your question, 150 miles is not very difficult for someone in good shape, and to do it over 2 days is even easier, but you have to get started now, training to do a bit more each day. Endurance is not difficult to obtain as long as you work at it every day.