Chinese visa without booking a tour

We were told by someone that if we do not book a tour for our complete China visit it will be impossible to obtain a visa, is this true?

If we were to travel without a tour - we would be visits Beijing, xi'an, chengdu and Shanghai - we will be booking our hotels in advance (not our trains as we cannot book then before 18days in advance) would this be enough to obtain a visa or is it likely to get rejected without committing to a guided tour our whole trip?

Thank you