There are flowering meadows, dense forests, with the dramatic mountains feeding the many streams, rivers and waterfalls. A UNESCO Site, it is the second-largest national park in Italy, covering nearly 700 square miles and containing 80 villages. Besides the history of Greeks, Romans and others, during more modern history these mountains were plagued by roaming briganti (bandits). Today, you are safe from kidnapping or thievery--not to worry. If necessary, you can say your prayers at the largest monastery in Europe.
One method of getting a good taste of both the coastal beaches and mountains as well as the Vallo di Diano is to start at Paestum, moving down the coast visiting the various towns and points of interest, then after exploring Capo Palinuro, make a turn up toward the mountains and the valley, heading north again, thus doing a sort of loop of the entire region. There are many discoveries to be made in the Vallo...
If you are traveling with a 4 wheel drive vehicle, you can drive up toward Cervati and start your trek or cycling adventure from higher up the mountain. If you're into serious mountain cycling, this is the place for you. In winter, the place is well known for snowboarding. The views from the bald, rocky top of Cervati are amazing but during the journey you might come upon mountain goats, sheep, grazing buffalo, wild boar, wolves (yes, they have some here), hawks and eagles. The trails may also lead to waterfalls, majestic cliff overlooks, caves and even a tunnel or two.
Note: Although you can drive fairly high on the mountain with a 4-wheeler, this is serious back country. Don't travel alone. Cell phone service is spotty. Mountain rescue is fairly non-existant. Bring a hand-held GPS unit if possible. Day trips only--do not consider camping on the bare-topped mountain. Carry lots of water. If you are into more flat land cycling and trekking, consider trekking in the valley below.
the Certosa di San Lorenzo. I put "monastery" in quotes for good reason. Looking more like an over-indulgent palazzo on the scale of Versailles rather than a stern, stark monastery, the Certosa dates from 1306 and covers nearly a square mile and contains: 320 rooms and halls, a mile and a half of corridors, galleries and hallways, 300 columns, 500 doors, 550 windows, 13 courtyards, 100 fireplaces, 52 stairways (some are magnificent) and 41 fountains. And I haven't even talked about the huge formal gardens. I can't imagine monks here spending much time meditating and praying in their cells.
The tremendous central cloister (not exactly cloistered... more like a palace courtyard) is nearly 500 feet across and the largest in the world; there is a wood-paneled library; you'll find several ornate chapels complete with frescoes; and the grandiose kitchen fireplace supposedly was used to make a 1000 egg omelette in 1534 for Charles V.
Teggiano would be a practical place to stay for a few days to a week while exploring the rest of what the Vallo di Diano has to offer. If you decide to stay in the town, you can rent beautiful rooms in Castello Sanseverino or other apartments in the village for about $100 a night or less. I can imagine a one week stay in a Cilento coastal town like Santa Maria di Castellabate for exploring the coast or doing some boating, then another week in Teggiano while enjoying what the Vallo and surrounding mountains have to offer.
This hilltown is tiny--only 1/4 mile wide but has fine views of the Vallo. There is a small archeological museum and a 12th century castle. The other reason to stop at this village is to do some trekking in the nearby Arenaccia valley where you will see mountain torrents, waterfalls and many caves. (Click to see a map of hiking paths in Atena Lucane).