Peak District towns, villages, and footpaths are generally quiet and safe or busy and safe on summer weekends. As with anywhere in England, towns and larger villages can get a little boisterous at pub closing time.
Apart from during severe winter weather, all but the most remote areas of the Peak District are relatively safe. But the Peak District has several Mountain Rescue Teams who are called out regularly to assist people who have got into difficulties either through unforseeable accidents or all too often through lack of preparation or because of wilful disregard of the dangers. Those taking part in outdoor activities should be aware of the dangers and not exceed their abilities and experience. Cave and Mountain Rescue Teams can be contacted via the standard 999 emergency services number. The most dangerous areas, even on apparently benign summer days, are the peat plateaux that form the top of the highest peaks in the park, Kinder Scout, Bleaklow and Black Hill. The "old" Pennine Way route used to reach Kinder Downfall via Grindsbrook Clough and the Kinder Scout plateau, and many hikers still use this route, whether they are starting the Pennine Way or are on a day walk. After periods of heavy rains, the peat becomes completely waterlogged and turns into a dangerous bog, not unlike quicksand. There are no reports of hikers actually drowning in the bog, but there have been cases of lone hikers sinking too deeply to extricate themselves and dying from exposure.
The dangers are reduced significantly by following common sense: don't cross the plateaux alone; don't assume that warm, dry weather with good visibility will last more than the next hour you can't see the other side of the moor, so you don't know what weather is approaching; take waterproofs and spare warm clothing; let someone know your planned route, and stick to it; make sure you have a compass and know how to use it. When mist or rain descends and distant summits disapper, the flat tops of the peat moors are very disorientating, with no close summits or other landmarks that can be matched to even a large-scale map. Climbing in and out of the peat "groughs" soon destroys the best "sense of direction" and without a compass it is almost impossible to avoid walking in circles.
The mountain rescue teams are volunteers who put their lives on the line - they should be regarded as a last lifeline for people who have genuinely unavoidable accidents not as a "fallback" to compensate for ignorance, foolhardiness, lack of fitness, bad planning, poor equipment, or "fashion" sportswear and footwear.
If you are planning to cross the Kinder plateau for the first time, you may be slighlty safer if you go on a Saturday, in the hope that there will be a string of other possibly equally lost hikers to follow.
fees/permits
Entry to the National Park is free. Most car parks charge a fee roadside parking is difficult on some roads, and country houses whether private, or owned by the National Trust charge admission.
However:
The National Park is not owned by the state it is basically an area with more stringent planning requirements.
The Peak District is criss-crossed by official footpaths which are free to walk, and bridlepaths which are also open to riders and cyclists. These are moderately well-signposted where they meet roads, but are easier to follow with an Ordnance Survey map.
Many of the wilder areas are designated Access Land, where access on foot is permitted free of charge even off the footpaths, but subject to certain conditions and occasional closures.
Many popular areas are owned by the National Trust, who usually grant generous access to walkers similar to, and usually designated as, Access Land.
The Chatsworth Estate allows similar generous access to walkers.