In the haunting beauty of west Wales, an archaeological tour breathes life into the ancient world. Juliet Rix is transfixed

Clambering up a narrow winding path, I look at the cracked, grey rock-face to my right. "Can you see it?" asks Maria, my guide, and there emerges the outline of a cross. A kneeling- shelf juts out below, and a few coins have been pressed into fissures in the rock. "It is probably medieval," Maria tells me, "A best-selling book in the 1970s said this was the site of the Holy Grail - we got a fair few nutters up here after that. It is nothing of the sort, of course: this is solid rock and the cross is here because we are on the pilgrim route to St David's."

A little further along the path are some overgrown steps. Maria points out the little crosses carved on each one. "The Knights Hospitaller ran the route and collected payment from pilgrims as they went from holy site to holy site," she explains. "It was medieval Archeaotours," adds Mary, my other guide. "Thomas Cook with prayers."

Modern-day Archaeotours is a new two-woman band set up to bring alive the archaeology of Wales (of which there is a vast amount). Mary and Maria are a double act. They are both qualified archaeologists, and their style is all their own. Mary is a former primary school teacher, warm and comfortable-looking with long wavy hair. Maria is younger, a motorcycle enthusiast with two children and various tattoos. They finish each other's sentences and take the Mick mercilessly. They know their stuff, though, and are extremely attentive to their guests. Archaeotours' breaks are intended to be not only informative and intriguing but comfortable and pampering as well. "No need to bring the car," I was told. "We do the driving." So I ride up on the train to be met at Carmarthen station. My guides' enthusiasm is evident immediately. As we drive, they are constantly pointing things out: a hill fort, a deserted medieval village, a castle where Roman remains have recently been found far west of where the Romans were thought to have stopped.

They tell me my evening massage has been booked, "so you can relax your body as well as your mind" (and it does too), but first stop is a pub lunch. In summer they provide picnics.

Carreg Cennen, a 13th-century stone castle and a settlement since at least the Iron Age, sits atop a limestone crag. It is built on the edge of a sheer drop with stunning views. We wander through the ruined rooms. Then it's down a narrow staircase, along an enclosed walkway (Norman) and into a cave. Darker and darker, narrower and narrower it gets until we are right under the far side of the castle. Not much is known about this natural cave-tunnel, but it makes me wish I had brought the children.

Back in the light, Mary and Maria point out the bumps on the top of the surrounding hills - Bronze Age burial sites apparently - and the poor quality of the high ground surrounding them. This is the fault of environmentally unfriendly humans 2,500 years ago, says Maria. "There was more industrial damage in the Bronze Age than in Victorian times," she adds. I look incredulous as she continues: "Burning tracts of land, bronze smelting with arsenic and lead, cattle churning up the soil ... we underestimate our ancestors." This is clearly true at Pentre Ifan, a Neolithic burial chamber (about 4000BC) with a vast capstone and panoramic views over Newport Bay. Maria stands among the stones, verbally recreating for us the chambers of the past and the ways of the people who used them.

I am dropped back at my hotel, The Gellifawr, in the Preseli Hills, source of the bluestones used at Stonehenge. I sit by the open fire, eat a very good three-course dinner and leaf through a couple of books they have lent me. Had I slept well?, they ask as they pick me up the next morning. This is more than a concerned hosts' question. I have been sleeping, they tell me, under Carn Ingli (Angel Hill) where sixth-century St Brynach dreamed that he must follow a sow and build a church wherever she farrowed. The result was Nevern Church, in a delightful spot by a rushing stream. Although mainly Norman, it has older Celtic carvings.

The lord who allowed St Brynach to build his church lived at Nevern Castle, a little way up the hill, a settlement since the Iron Age and into Norman times. As at most of the sites we have visited, we have the place to ourselves. Mary brings out a Thermos and pours us mugs of hot tea. We wander, sipping, along a raised bank next to a ditch. "This is the outer defence of the Iron-Age fort," says Maria. We round the corner into a broad open space with a mound on the far side. "Norman motte and bailey," Maria continues. "This area would have been crammed with wooden buildings - like an enclosed village. Busy and noisy.

"Close your eyes. What can you see? hear? smell? horses ... people ... human excrement ... sweat." I open my eyes and all is peace again. I take a good draft of warm tea and wander up to the top of the mound. This is the way to do archaeology.

A weekend Archaeotour (Friday noon to Sunday night) costs from £295 per person full board (excluding rail travel and treatments) (01267 267636;