I once set out to go through every single London Underground station on the network in one day with a few friends as part of a university joke. It was very, very boring - but we kind of managed it. This was back in the days when you could drink on the trains. We all had a six pack each to get through to keep us occupied and we began at 6am at Woodford on the Central line, did the Hainault loop and Woodford to Epping and back. This took over an hour.
Woodford to West Ruislip. Then Back into London, buy now it was about 9am.
Full clockwise circuit of the Circle line start/finish Notting Hill Gate.
now 10am, Hammersmith and City NHG to Hammersmith and then full length to Whitechapel.
District eastbound to Upminster, then westbound to Richmond.
Back on ourselves up to Earls Court then down and back to Wimbledon. It's now lunchtime and we're all quite drunk.
Buy another six pack and have some food - getting a bit fed up with underground trains now, so we give ourselves a 1hr break and get the bus to South Wimbledon.
Northern line to Morden, then full length to Edgware, down to Clapham on the Charing X Branch which we hadn't done yet, cross over to a High Barnet Branch at Euston. Don't bother with Mill Hill East.
It's now about 3.30pm
We do the full lengths of the Victoria (fairly quick), Bakerloo (quick), Piccadilly (back then Heathrow was a circuituous turnaround - no terminal 5 station), Jubilee, (quicker). East London (quick), but don't bother with New Cross Gate. It's now about 7pm.
Have another well deserved break above ground. Toilet stops, etc
We finally finish with the Waterloo & City over to Bank, and a full length Aldgate to Amersham on the Metropolitan.
We called it a day at about 10pm, having not done the Docklands but having done most of all the other lines
We did about 200 miles in one day (we reckoned) and covered 95% of the network if you don't count Docklands, and 'doubling up areas' such as where there are three lines using the same bit of track (e.g. circle line), or two tracks running more or less together - such as Piccadilly, Central and District lines in West London.
Quite impressive but I wouldn't do it again, even with the friends and the beers - it got a bit boring! The worst bits were trying to find toilet stops for everyone.