I've got the itch. Again. And I'm supposed to have settled down. Having hit 40, with an albatross of a mortgage, my trusty rucksack has all but been consigned to the loft. But when I saw a photo of the rather delectable Gael Garcia Bernal striding manfully across the Andes as Che Guevara, I knew this particular itch wasn't going to go away. Especially not now I've been made redundant and reversed the "cash-rich, time-poor" paradigm in one fell swoop.

It' s 15 years since I sewed secret pockets into my jeans and flew to Bogota with the aim of reaching Tierra del Fuego. That was the plan anyway.

By the time I'd salsad my way round Colombia, lived with an Ecuadorian family who thought my nascent Spanish was the funniest thing they'd ever heard (they'd be proud to know I can still swear like a trooper), limped along the Inca trail (I had to scrounge coca leaves from the locals to get over Dead Women's Pass) and had one of the best nights out of my life drinking pisco with the inhabitants of a small Bolivian town (followed by one of my worst mornings after), I only had time to make it half-way down Chile to Santiago (on the cheap coach - 24 hours sitting bolt upright, with The Terminator dubbed in Spanish on continuous loop) and my flight home.

I want to hit the road again. The same road in fact - the Pan-American Highway- from the Alaskan wilderness to the wilds of Patagonia. I have some questions that can't be answered sitting behind my desk or on the sofa: Is there a man behind every tree in Alaska? North or south side of the Grand Canyon? Is Nicaragua really the friendliest country in Central America? Aztecs, Mayas or Incas? I want to go whale-spotting in Baja California, get drunk on mezcal, ride on the Copper Canyon train, learn to dive in Honduras, marvel at the pyramids of Tikal in Guatemala, eat tacos from a market stall, climb a volcano in Nicaragua, explore cloud forest in Costa Rica, sleep in a hammock and, this time, I want to get to Tierra del Fuego.

My first trip was pre-email, pre-internet - almost pre-computer. I kept a journal that no-one got to read - it disappeared somewhere in the Atacama desert. There's probably an internet cafe on the very spot. I remember giving family and friends a detailed itinerary that derailed after the first week. For news from home I had to rely on the arbitrary nature of South American post restante services. This time will be different. This will be a trip I can share. And not just accounts of spectacular monuments and lush scenery, but the day-to-day encounters that make travelling so fascinating, frustrating and ultimately so irresistible.

Help me scratch my itch, jettison my suit and bring my rucksack out of retirement. Put me back on the road - I promise you an amazing ride.