The first thing to know is that you have exactly 11 days to take advantage of probably the best travel deal of the year: the cut-price French Rail Pass. Buy before the end of May, and begin your travel before the end of August, and you may wander anywhere you wish on the splendid SNCF network on any three days in a month for £92. Travel with a partner and the price falls even further, to £75 - roughly the price of a one-way ticket from Lille to Nice. That is for second class; the price for first is only £20 more. So I ploughed some of my savings back into an upgrade that, initially, proved difficult to justify.
Some of us are just not cut out to be first-class travellers. When I boarded the train in Arles, destination Avignon, I temporarily forgot I had bought the posh version of the French Rail Pass. I found myself in first class and, as a creature of habit, walked through to the cheap seats. The information pack you get with the rail pass warns that "a pass is valid for travel in the class for which it has been issued", but then concedes that "(first class passes are also valid in standard class)". Just as well, because my next trip was no more luxurious than the first. At Avignon's Centre station, I was so mesmerised by the architecture that I did not watch the train as it came in and had no idea where the first-class compartment might be. I was only going one stop, so I stayed in second class.
THIRD TIME lucky? It was bound to be, because I was travelling on a Train à Grande Vitesse. Every passenger on French high-speed trains must have a reservation. This requirement detracts from the freedom and flexibility of the rail pass, because you still have to join the often-interminable queues at French railway stations. But as a first-class traveller, when finally you reach the front, you can feel momentarily superior while handing over €3 (£2.20) for a reservation.
On the trip from Avignon to Nice, the real value of travelling first class became clear: when the timetable falls apart, at least you are sitting comfortably. Even without the strikes that frequently disrupt SNCF services, every train I caught was late. At stations and on trains, information varied from non-existent to patchy. Good humour lasts longer when you have more space to relax. But while we waited outside Marseille station, some of the business travellers were getting twitchy about their laptop batteries. Unlike trains in the UK and Germany, the now-threadbare TGV carriages do not have mains power.
THE FINAL leg of my Tour de France began where the world's leading cycling event will start on 1 July: Strasbourg. A TGV connection to the easternmost city in France is under construction, and will halve the present four-hour journey time to Paris. But for now, travellers must make do with refurbished "classic" trains. These are no faster, and you have to queue up for a reservation for a train that, on a Wednesday afternoon, should have plenty of seats. But when I paid my €3 I was told there was no space in first class: either you take a second-class seat or you can't get on, was the message. The train approached Paris behind schedule. As the suburbs thickened I walked to the front - and discovered two almost deserted first-class carriages. What a first-class fool.
NOT MUCH happens at Larissa railway station. The ungainly capital of the Greek region of Thessaly looks as though most of it was put up with unseemly haste the week before last. The station is a good example of clumsy modern architecture; its main point of interest is the reminder that the "no photography" rule applies to Greek railways as well as airports.
Last Saturday afternoon, hardly anyone was around. Even though the Greek railway network is rapidly improving, many of the locals favour buses over trains. So I was able to take my time in buying a ticket for the 4.10pm Macedonia Express. This Inter-City train begins in Thessaloniki; its name is a reminder that Greece claims nomenclature rights to the former Roman province. The train's destination is Pireaus, the busiest ferry port in the Mediterranean. And shortly before it arrives there, it calls at Athens. Which is where I was heading.
The fare of €10.70 (£7.50) seemed cheap for a journey of over 200 miles on an express train. When I checked the ticket, the reason was plain: the booking clerk had disregarded my request to travel on the express, and had sold me the cheapest ticket going. This applied for an evening all-stations-to-the-Acropolis that arrived shortly before midnight. She cheerfully changed the ticket to one for the Macedonia Express, in exchange for more than double the original fare. Equally cheerfully, I handed over the cash - but then ruefully realised that I am inevitably consigned to the cheap seats, be they in France or in Greece.
French Rail Pass: book through Rail Europe (08705 848 848; www.raileurope.co.uk)