Prahova

Set expectations correctly and Peleș becomes one of the best visits in the country. It is not medieval and not a fortress: it was built between the 1870s and the 1910s as a summer residence for Romania's first king, in a German neo-Renaissance style with timbered gables and pointed turrets, set among conifers on a slope above Sinaia. The exterior is handsome. The interior is why you come. Around thirty of its rooms are open on the standard route and they run through a sequence of national and historical styles — a Moorish salon, a Turkish room, a Florentine one, a Venetian one — with carved walnut panelling of remarkable quality throughout, stained glass, Murano glass and Meissen porcelain, a full armoury of several thousand pieces, a small theatre, and a central hall with a glass ceiling that could be retracted mechanically. It also had electricity, central heating and a lift from the outset, which was unusual for a European palace of its date and is the sort of detail that makes the place feel less like a museum. Photography usually carries a supplementary charge and shoe covers are issued at the door. Go early: the queue in summer is long and the interior is much better without a crowd in it. A short walk away, Pelișor is the smaller adjacent residence, done in an art-nouveau register, and it is quieter and more intimate — many people prefer it.

From Bușteni, a few kilometres up the valley, a cable car climbs the steep wall of the Bucegi massif to a plateau at around two thousand metres — a broad, bare, windswept upland quite unlike the forested valley below it. Two rock formations on the plateau are the objective for most people: a tall outcrop whose profile resembles a face when seen from the right angle at the right time of day, and a cluster of mushroom-shaped pillars nearby, both produced by wind erosion of unevenly hard rock. There is a monumental cross on the ridge above Bușteni, visible from the valley and lit at night, and a network of marked paths running across the plateau and down through the gorges to the valley floor. Walking down rather than riding both ways is a good day for anyone reasonably fit, with the caution that the descent is long and the weather up there changes with no warning. The valley towns each have a character: Sinaia is the grandest, with the palace, a monastery that gave the town its name and a belle époque casino; Bușteni is the mountaineering base; Predeal, at the top of the pass, is the highest town in Romania and the most straightforwardly a ski resort. All three sit on the railway, which makes this one of the few mountain areas in the country that is genuinely easy without a car.

Two things east and west of the valley are worth the diversion. At Slănic Prahova, a disused salt mine has been opened to visitors and it is far stranger than that sounds: enormous rectilinear chambers cut hundreds of metres into the rock with walls of banded grey and white salt, a constant temperature, air that is used therapeutically for respiratory conditions, and enough space inside for a football pitch and a small lake. It is a genuinely surreal hour and excellent with children. To the east, the hills of Dealu Mare form one of Romania's most significant wine regions — a long south-facing belt of vineyards producing serious reds, with several estates open for tastings and a landscape of low ridges and villages that is pleasant to drive without any fixed plan. The county seat, Ploiești, holds a clock museum with a collection far better than the city's reputation suggests, and is otherwise an industrial city that makes no particular claim on a visitor. And at the head of the valley the road crosses into the next county, where the Brașov guide picks up the Saxon towns, the fortified churches and the other side of these mountains.

The single most useful fact about this county is that it is easy. The railway from Bucharest runs up the valley to Sinaia, Bușteni and Predeal and on to Brașov, taking a couple of hours from the capital, and the transport guide rates it among the more scenic mainline journeys in Europe — which means Peleș and the Bucegi cable car are both reachable without a car, from either end. That makes the valley an unusually good option for a short trip: two nights in Sinaia gives you the palace, the plateau and a monastery, with no driving at all. For anyone on the country's wider circuit, the honest advice is to stop rather than pass through — an itinerary that goes Bucharest to Brașov in one hop drives past the best interior in Romania at seventy kilometres an hour. Season: the palace closes for maintenance for a period each year, which is worth checking before building a day around it; the plateau is a summer and autumn proposition, superb in September; and the valley is at its busiest in the ski months and on any summer weekend, when Bucharest arrives en masse and the road back on Sunday evening is to be avoided.