The Beiras, with their many remote villages, are suited to exploration by car. Distances between major points are short; there are no intimidating cities to negotiate; and except for the coastal strip in July and August, traffic is light. Roads in general are good and destinations well marked; however, parking can be a problem in the larger towns.
Allow plenty of time for journeys the moment you are off the main highways. Many of the mountain roads are switchbacks that need to be treated with extreme caution. In addition, you are almost certain to get lost with appalling signposting (usually hidden around the corner or behind a tree) and nightmarish one-way mazes in every town, from the smallest hamlet to the largest city. If you get to your destination without going around the whole town three times, consider yourself lucky. Even the locals admit to getting lost on a regular basis.
Drive defensively at all times; Portugal has one of Europe's highest traffic fatality rates. Among the worst roads in the country for accidents is the IP5 heading inland from Aveiro to the Serra de Estrela.