If you're traveling by road, expect heavy traffic out of London on weekends. Travel time to Manchester or Liverpool from London via the M6 is 3 to 3½ hours. Although a car may not be an asset in touring the centers of Manchester and Liverpool, it’s helpful in getting around the Peak District. Bus service is quite good, but a car allows the most flexibility.
Roads within the region are generally very good, but the deeper you get into the countryside, the more likely you are to encounter narrow, one-lane farm roads once you turn off the main routes. In summer, Peak District traffic is very heavy; watch out for speeding motorbikes, especially on the A6. In winter, know the weather forecast, as moorland roads can quickly become impassable.
In Manchester and Liverpool, try to sightsee on foot to avoid parking issues. In the Peak District, park in signposted parking lots whenever possible.