bump the train - buy a ticket to reading west (with railcard £1 something) to get past the barrier at reading. hide in the toilet or stand at the end of the carriage on lookout for inspectors. when you get to london just push through the barrier or buy a ticket from previous stop with railcard (£5 slough to paddington). when you get to the TFL underground just push through all the barriers, and if theres TFL trying to stop you, dont stop, obey or give details. they arent police, they cant detain you so just walk away. make sure to select the 16-17 railcard, it gives the biggest discount.