After two weeks and 3,000 miles of empty highways in Montana and Wyoming, through to Tombstone, Arizona, this was our last day and we couldnt bear to leave.

Before heading northwards alongside the Rio Grande to Albuquerque for our flight to New York what if, with our remaining few hours we maybe squeezed in a quick look at Mexico?

The guidebooks oozed praise for the local people, their fantastic food and exciting markets, making a crossing into Mexico a must. So, why not?

Wed originally intended an ambitious three-mile hike to Fort Bowie, where in 1873 the dying Apache chief Cochise had surrendered, and later Geronimo too, when all hope had gone for his tribe to live on their own land. Away to the distant south, the fort lay beyond sifting sands that danced into duststorms and mini tornadoes, easily persuading us to abandon our plan. Instead, our destination would be El Paso - The Pass of the North - a one horse town from the many Westerns of my youth, 300 miles east of Tombstone. Wed do it comfortably in five hours. At El Paso, where Indian trails and gold hunting miners once crossed the Rio Grande, we would cross the river on foot, touch Mexican soil in Ciudad Juarez and take a few photos before our dash to Albuquerque. Simple. We should have known better.

The guidebooks had neglected to mention that Ciudad Juarez, its outstretched fingers sprawling into the foothills of northern Mexico, has more gangster-related murders and corruption stalking its streets than any other city on the whole continent. So, in happy ignorance, this was the notorious border city whose portals we were about to enter by mistake. At the wheel of our hired sports car that hot September day, Catherine and I along with the rest of the world, could not have guessed that 400 assassinated Mexicans and Americans were about to be discovered within its boundaries.

Yet its past was no less violent; bandits roaming the hills and desert, holding up trains and generally raising hell north of the Rio Grande until the outbreak of World War One. When Pancho Villa with his Porfiristas won a decisive battle here in 1911 against the dictator Diaz, Americans on the north side of the river watched the fighting from the safety of El Paso housetops and passing trains. In 1912, to avoid recapture after escape from jail and before meeting up with Zapata in Mexico City, Villa sat tight in a downtown El Paso hotel.

In hindsight perhaps my daughter and I should have done the same.

El Paso was further than wed imagined and through the searing heat of an empty highway across New Mexico we could have been forgiven for believing we were the only humans west of the Pecos. Roadsigns at the outskirts of one township, proudly declaring an unbelievable ten citizens, called upon everyone to unite and support their local sheriff in the coming elections.

Lulled into believing we would simply drive up the main street like first time cowboys, 300 miles later and before we could cry yeeha, we found ourselves swept unimpeded through the checkpoint over the border and into Mexico. Hemmed in on all sides by eager home-going traffic, with no obvious escape what had become of El Paso? That friendly local sheriff? The safe parking? And with no insurance for south of the border.

Our only thought was for flight but, with not one word of Spanish between us, the signs conveyed absolutely nothing. Once across the Rio Grande everything familiar had disappeared and, in the heart of Ciudad Juarez, our promising right turn into a maze of one-way streets quickly became the road to nowhere.

A bicycle bumped into our side - a ploy to offer us the brightest lights its riders city had to offer. Questions were useless for, beyond those few words, his English deteriorated into a torrent of Spanish, ever more angry as our hastily closing window blotted out his voice. Foolishly following a bus, hoping it might lead to a depot of some kind, we soon realised we were heading out of town and deeper into the hills. Suddenly we became very conscious of being two women alone, lost, in a conspicuous luxury car with Arizona plates - a sure giveaway - and painfully aware no-one on earth knew where we had come.

Anxiety kept doors firmly locked, our feet failing to touch the sand blanketed ground. We forgot to take photos of the beautiful black haired children, the houses or the derelict cars and vans littering the roadside. Worn out buses rattled past, hot like the desert wind, undecipherable destinations scrawled in chalk across their windscreens, while twilight gangs worryingly gathered at every street corner.

Under darkening skies we spotted what could be our last chance; an exit unseen in our earlier peregrinations. Hooray, but how to reach it, across six lanes at traffic lights? We couldnt afford to pass it by; it had to be then or never. The matter of insurance feebly raised its hand in protest. But, closing our ears and eyes to a cacophony of horns and no doubt many blaspheming Mexicans, at the change of lights we revved across their path with only one goal in mind. Reckless cowboys of the past would have been proud.

At last safe and smug in a queue it occurred to us we had no proof wed not been loose in Mexico for weeks, while up ahead at the border proper, guards searched every vehicle. Roadsigns in English warned of forbidden cargoes. Alcohol, arms, soil, drugs, fruit and emigrants.

At such aspersions on our integrity rational thoughts returned for, despite having no Mexican entry visas, in our wallets were petrol and motel receipts from the night before. Of course we were innocent. Spirits high, our excuses were word perfect long before the moustachioed guard reached for our passports.

Nationality? Arms, alcohol? Prepared to plead for mercy and throw open boot and bags: English, senor. A wide smile. A touch to his cap. Ah, Ingleesh! Si!

Of course. One little word explained all. His expansive wave ushered us forward - they didnt even look inside - on to the bridge on El Paso Street. Beneath us the Rio Grande flowed uncaring and as darkness fell we were on our way. Too late now, our Pass to the North gave only tantalising glimpses of the majestically titled river, its waters pale, gleaming under New Mexicos vast moonlit sky. Turning our Juarez experience over and over, we hadnt stopped talking until, pulling into an empty rest area we unlocked our doors and climbed out into the desert.

Through the hot night, oblivious to the rattlesnakes hunting in its comparative coolness, from the dashboard we heard our only Brule CD playing their haunting Native American songs; repeatedly falling on deaf ears it hadnt stopped since our straying over the border six hours before.

After terrifying revelations in a TV documentary some weeks later we darent conjecture what might have happened if wed run out of fuel, broken down - if wed not escaped from Ciudad Juarez before dark.

Now, Im not sure whether my husbands puzzled looks are baffled pride or amused tolerance when we tell him that next year were planning to cross the border - on foot - at a little cowboy town called Nogales.

Above; Shirley and Catherine in Arizona.