Travel by bus is a wonderful way to reach almost any place on earth - or at least on land. There's hardly a corner of the planet that isn't somehow serviced by bus.
And often, cheap bus travel can't be beat when it comes to saving money.
Taking the bus is also great fun! You can see what's around you close up, and in developing countries you're packed like sardines. That's not so much fun but you'll never have a better chance to get so close to the local population.
In the case of intercontinental long-distance travel, the bus is ecologically friendly, reducing your carbon footprint by up to 80%.
There's nothing dull about going by bus in some countries. Forget the sleep, boring long-distance buses that ply North America.
On a bus in Mozambique a local farmer thought that a seat for myself was far too wasteful and promptly plunked a box of newly-hatched chicks right on my lap.
In the Philippines, jeepneys are riots of colors, with prayers or brand names wildly painted all over them. And you'll know where all those old-fashioned American school buses went when you travel by bus into the mountains of Panama (British buses end up in Malawi). Throughout Africa, the matatu or similar minibus is designed for 15 or so people but usually carries 40 or more - inside, outside, on top.
Travel by bus also makes sense. Like cheap train travel, buses have their own passes and special deals. Many of these make travel a breeze.
In South Africa, the Baz Bus operates on a hop-on hop-off basis along the coast from Cape Town to Durban and Johannesburg. I spent two weeks on this route in its early more rickety days (before the semi-luxury vehicles, as they are now called) and saw a huge chunk of South Africa at a manageable pace - a bit of a hostel on wheels.
If Turkey is your destination, try the Fez Bus from Istanbul to Ankara right into Cappadocia.
In Europe, look for all your bus schedules and prices here. Several bus lines cover various key countries and buses are modern and well equipped. Depending on how many stops you plan to make and how frequently you'll travel, this can be an alternative to railpasses.
The other great bus deal in Europe is the Eurolines pass, with a continent-wide network for just a few hundred Euros. This is not an economical alternative if you're going point-to-point, but if you plan on spending several weeks criss-crossing the continent - routes range from Madrid to Gotheborg to Tallinn to Rome - its rates are hard to beat.
In New Zealand you can try Kiwi Experience and in Australia Ozexperience. In the US, you can't get much cheaper than BoltBus, which travels up and down the Eastern seaboard from Boston to Washington with low low fares.
A very long distance overland voyage is provided by OzBus, which plies the London-Sydney route - 20 countries in 13 weeks, with several departures a year. This long-distance alternative is almost a cross between overland tour and bus transport, but still fulfils the requirements of backpacking women who prefer to travel by bus.
Plenty of cities have hop-on hop-off services, although they aren't usually as economical as their long-distance counterparts. Still, these buses beat taking a tour and gives you a lot more freedom. Some of the ones I'm familiar with include London, Lisbon, Barcelona, Kuala Lumpur, New York and Toronto.
Many countries have excellent internal networks of both buses and roads, and catching a bus is only a question of getting yourself to a bus station. Switzerland for example has an excellent network of affordable postal buses - they deliver mail, and carry passengers while they do their rounds. So wherever there is postal service - and that is in every single village - you can travel by bus.
A word of warning though: travel by bus isn't for the faint of heart. The music is often loud, no smoking signs may be ignored, the driver may be drunk or high (especially if it's a long route and he needs to stay awake), the vehicles can be mechanically unsafe or obsolete, and the roads downright dangerous so make sure you read up on road safety abroad.
In some parts of the world, opening a window is not deemed acceptable. When this happens in the baking heat, you may well wish you were on that air conditioned train instead!