NEARLY four years after he set out on April Fool's Day from his country town in the

United States to begin a trek around the world, Tom Stone has made it to Cambodia.

The latest of 20 countries he has visited, Cambodia has a special significance for

Stone. It was here, 25 years ago, that his brother - CBS News journalist Dana Stone

- went missing, believed killed, while covering the Cambodian war.

For Tom Stone, visiting Cambodia is a way of laying old ghosts to rest as well as

pursuing his quest to see the world.

His expedition, begun April 1, 1992 - "I couldn't think of a more appropriate

day" - has seen him walk more than 12,000 miles.

A former sergeant in the US army, who signed up within 10 days of leaving high school

in 1971 but did not serve in the Indochina battlefields his brother covered, Stone

left the military in 1992.

"The military is a very volatile lifestyle and you start having dreams of symbolic

things like sailboats and things like that. I didn't have enough money for a sailboat,"

he jokes.

He decided to walk instead. Inspired by the stories of people who had done the same,

he dreamt of traveling the world by foot.

With no wife, children or "responsibility", he sold his house, rustled

together his money and a backpack full of gear - most of it since discarded - and

plotted his expedition.

"Once you tell people you want to walk around the world, they look at you very

strange. They either want to lock you up or they are polite but think you're lying."

Setting off down the road from his home town of Pomfret in rural Vermont, he remembers

mentally adding up how many people he would be too embarrassed to see again if he

didn't make it.

He was accompanied for his first half a mile by a group of local schoolchildren,

with whom he has exchanged letters throughout his trip.

He describes it as "mental protection." An avid mountaineer and a former

army medic, Stone wasn't worried about his physical health but realized that his

success would depend more on his mind than his body.

"If you're hurt, you can rest. If you're tired, you stop. But if you're unhappy,

you might as well just go home. It will become no more than a military campaign and

you're going to alienate everybody you meet."

So when he stays somewhere long enough, he drops a line home to his local school

with his latest address. His spirits are usually boosted by a mailbag full of letters

in return from curious children.

He began his journey hacking his way through the snow-caked Appalachian Trail, which

carves its way from Georgia to Maine along the US east coast, before reaching Canada.

Since then he has been to Ireland, Scotland, France, Belgium and Luxembourg ("I

was in Belgium for two days, I thought I was in Luxembourg"), Norway, Sweden,

Finland, spent 18 months in Russia ("big country"), Japan, Korea, China

and Vietnam ("there's a lot of people, it's damn hard to find a place to sleep"),

among other countries and a host of islands, including several whose names he has

difficulty remembering.

Stone doesn't claim to have walked throughout all the countries, but charts a route

depending on the advice of locals.

"I've traveled enough to know the bus doesn't always stop at the heart of the

country. I thought if I walked, I would understand more about the people. It's not

true, I'm sure."

His favorite memories are the "small things": a potato given to him by

one poor boy, the only present he could afford; a welcome glass of milk from a Siberian

woman after hours of walking in the middle of nowhere; the child who, entreated to

ask Stone anything at all, inquired: "How much does chewing gum cost in the

US?"

He travels light, usually sleeping in a tiny Bivvy Sac tent wherever he can, in ditches,

snow caves or on the side of roads.

Most recently he was bedding down in rice paddies in Vietnam, where his trip took

on an element of nostalgia over his brother's part in Indochina's tragic history.

Dana Stone disappeared April 6, 1970, with Time magazine's Sean Flynn, son of the

actor Errol Flynn, while covering the communist Vietnamese invasion of Cambodia.

The pair were last seen on motorcycles about 10 miles from the Vietnamese border

in Svay Rieng, a day after five other journalists disappeared in the same area.

Tom Stone says he never really knew his brother, 13 years his senior, but acknowledges

a degree of "hero-worshipping".

"Dana did whatever he wanted to do. He worked in gold mines, in the wheat fields.

Dana was fearless, and he had a certain amount of finesse."

Stone probably won't walk through Cambodia - for security reasons - but intends to

say a couple of weeks, seeing the sights and searching out anyone who remembers his

brother.

From here, it will be on to Laos, Thailand, Malaysia, Indonesia and wherever. As

he puts it, "I've got no plans for next two years" - just to keep moving,

meeting people and watching life go by.

Despite clocking up about 4,000 miles a year walking - he has lost count of how many

pairs of boots he has exhausted - he says the life is easy.

"It's like going to the theater. There's always something going on, something

to watch. If I'm bored if means I haven't been paying attention."