This has to be one of the most awesome cycling trips I have done for the sheer scale, and the fabulous journey along one of the worlds highest motorable roads. It was especially good as whilst cycling you go from A to B with no mandatory road transfers so you get to cycle the whole way from Leh to Manali if you want to. It was VERY well organised and catered for people going at different speeds with enough guides to cope with this so there was no pressure to hang back if you want to go fast or pressure to speed up if you want to go slower and stop to take photos etc.
You don't have to be a fitness fanatic, as long as you are confident about the long days on a bike, and have some basic off road skills as the roads are quite bad in places. It is tough though - wake up tea whilst camping is at 6am, cycling at 7.30am, and then a long day, so don't expect lie ins or leisurely starts, and do expect to feel quite tired after this holiday. It is fully supported however and there is an option to go on the bus at any stage.