I want to make a trip from Manchester to countryside. Where shoud I go? Are there some interesting castles or remains, some natural phenomenons or whatever... And what should I use for transport? Train, bus, rent a car?
You are lucky: Manchester is really well situated. Go North West and you have the whole of the Lake District; go North East and you have the Yorkshire Dales, or you have the whole of Derbyshire on your doorstep.
Most of these are best explored by car. There is a little valley in the middle of derbyshire called Monsaldale : great pubs around, wonderful countryside and walks nearby. Few tourists (any) make it here.
Edale is another more obvious gem. almost 8 years ago