An old guy told me if your chain breaks while you are out tie it together with a lace and pedal then back pedal then pedal and so on till you get home.
I have never had to do it but you never know.Another tip he gave me was if you get a puncture you can't fix put the tire beads around the outside of the rim
and you can get home almost as quickly as normal.I have done this and it does work but not kind to the rim or tire.