what was the three friends initial plan for megna charta island? why did the men not reach magna charta when they had planned?

That morning, the men arrive at Magna Charta Island, near Runnymede. As the name suggests, Magna Charta Island is where King John signed the Magna Carta in 1215. J. speculates at length about what it would have been like to be a peasant living in Runnymede at the time of the event.As the men approach Magna Charta Island, Jerome imagines what it would have been like to be a peasant when King John was forced to sign the Magna Carta in 1215. To a certain extent, this passage tips Jerome’s political hand. It is notable that despite his middle-class background (and his patronizing attitude toward ‘Arrys and ‘Arriets in the previous chapters), he identifies with the peasants rather than the bourgeoisie or the nobles. His positive description of the Magna Carta as “the great cornerstone in England’s temple of liberty” also hints at Jerome’s populist sentiments.

The three men wanted to spend their first night on Magna Charta island. But they were not able to reach there that night because all of them were extremely exhausted and didn't want to travel that far in the night. So they decided to stop earlier.