Rollapaluza

Go to a gym and use their spinning machines.

This. Or use the standard gym bikes on the lowest resistance available.

Get on a turbo, 200rpm bursts for 20 seconds. Repeat after a rest. For authenticity, drink between reps. You need to handle 220+ to trouble the winners.

Most definitely not for me, but whatever floats your boat.

200/220rpm? We used to get 300rpm+ out of the gym bikes in Newport. We used to get some strange looks from the other 'normal' keep fit people who'd struggle to get out 60rpm

The most amount of efforts you do at the race is 5/6 isn't it? No point doing much more than that.