End of the Line - Underground Adventures
Part I - Amersham/Chesham and Heathrow Terminal 5
The London Tube map is a recognised worldwide icon of simplicity. Using cues from electrical wiring diagrams: destination and not distance becomes the important feature. For almost all visiting London, the central zone (zones 1 and at a push, 2) will be the only area under consideration. Reassuring guide-book names such as Oxford Street, Bond Street, St Paul's and Westminster are tightly clustered, meaning exposure to the entire network will be limited on short stays. However, if you plan to live in London you must pick somewhere according to both transport links and affordability, which inevitably translates to further out. If flat-hunters are pushed to the end of the line, it's usually simpler to avoid the Tube and get a fast train in. One day however, there may be a spontaneous temptation to head out, rather than in, and observe first-hand what dragons lurk at the end of these Underground lines.
Amersham/Chesham (Zone 9) - Metropolitan Line
Since Ongar closed, Chesham and Amersham are the furthest two stations from London and well outside the M25 (London orbital motorway). Chesham 
is the more distant, on a spur from the main line and is noted for almost nothing. Recently it's experienced some of the UK's coldest temperatures and revelled in a column centimetre or two (hot off the press, Chesham was the coldest place in the UK 'again' last night -11C).
Shopping on the High Street is possible, but Chesham is also noteworthy for the number of closing shops during the UK's bottomless recession. Pop-ups and pound-shops patch over the main thoroughfare, like temporary caps in a row of broken teeth. There's an excellent pub in 'Old Chesham' (The Queen's Head) but that's a 15 minute walk away, hidden beyond the wit of all but the most intrepid. Nope, just stay on the Tube and it will slide majestically away in the direction it came. Give it around 5 minutes.
More upmarket, Amersham is if anything, more baffling than Chesham. It has several loose ribbons 
of retail activity, rather than a discernible town centre, but don't plan to stumble over them, without prior orienteering-prep. Confusing town-planning that's aimed at car-users, means there's little to see in this commuter town. It does have a bijoux 'Old Town', but that's a stiff hike away. 'High & Over House' built in 1929 by Connell in the Modernist style, is a nationally significant piece of architecture twinkling in the nebula of commuter dwellings, but twitching curtains and neighbourhood watch signs (the kind featuring meerkats), will discourage half-hearted attempts to track it down.
Line, flavour and who you'll see
Metropolitan is the Grand Dame of the Tube system, and this branch is converted steam railway track from the Victorian era, not electrified until the 1960s. It's economically a middle-to-upper management commuter zone. The train is mercifully fast from Baker Street, meaning it's choosy about where it stops on the trundle out. Meandering through a fair share of deprived areas and Chesham itself is no beauty. The chances of being approached by a young mum with one hand out-stretched, clutching a toddler, remain medium-to-high; especially around the Wembley Park area. People do talk on this line occasionally and giving up a seat for someone has been witnessed. On the downside, it's nearly all overground, so phone chat is constant. Hot-food snacking is unusually common and on the last train out, near mandatory.
In summary: If you've a few hours to kill, own a camera and have wondered to the point of action, what a Tube train picking it's way through dense woodland feels like. Charge up the Oyster for an eye-popping excess fare (well into double figures) and 'go west(-ish)!' Just don't tell everyone, or you'll probably get teased. Alternatively watch the YouTube clip and pretend you did it years ago - when it was cool.
Someone's usefully gone and filmed a high-speed trip out to Chesham on Youtube.
Heathrow Airport (zone 6) - Piccadilly Line.
Piccadilly is London's premier tourist shuttle. Before they modernised the stock, the old trains had extra spaces between seats with directions to pile your 
suitcases up; singling the line out as jet-set flavoured since the 70s. Despite building two rapid transit rail services to-and-from Heathrow, their sobering cost bats many visitors straight back to the cheaper Tube system. You'll spot them on the way into the West End, nervously clutching bags and contemplating the featureless moonscape of Boston Manor. Or puzzling why Hounslow warrants three Tube stops. (It doesn't).
Chocolate box Britain this is not, but it is the real London. The more interesting one, and observing this sheep-dipping process of newly-arriveds can be entertaining. For those leaving at Piccadilly Circus, Leicester Square or Covent Garden, the reassuring teddy Grenadier Guards and red bus tea-towels, will still many a-beating heart.
Beyond the West End, the line meanders through Holborn and the tourist hotel hotspot of Russell Square & Bloomsbury before swinging north and heading up Green Lanes towards Wood Green and beyond. Save that for another day.
Line, flavour and who you'll see
Piccadilly is the proverbial tourist carousel. Flyers and workers make up the bulk of the passengers, 
though it's not recommended as a commute into the West End and City. It runs frequently, but offers an uncomfortable mix of green visitors (blocking the doors, revolving with rucksacks and similar) plus weary workers - though weekend mornings it's shoppers heading into town.
Heathrow is vast, Hatton Cross is also part of the airport complex, though if you don't work at British Airways, there's little point getting off there. It's possible the airport could provide a destination of sorts, if plane spotting floats your boat (or rather, trims your ailerons), but most people living in town see and hear them often enough as it is. Other cities sensibly position their airports on the far north or south limit, to avoid planes over built-up areas. Heathow's position due west, ensures a steady stream of moaning jets overhead.
In summary: long, tourist-choked, pokey, bumpy, deep, but with a cracking smörgåsbord of destinations. Ranging from Osterley Park in the south to Ally Pally (Bounds Green) in the north; just get beyond that spider's web of Piccadilly Circus to Covent Garden. There's a whole lot more to see besides.
Noisy planes overhead is irritating for Londoners, but few cities give you such a view of the sights as you come in to land. Arriving at Heathrow, from Docklands in the east.
