Wales and North Yorkshire are best for waterfalls and N. Yorks is a bit too far North for your trip. Instead of the M6, go to Ross and then up the A49 through Herefordshire, Shropshire and Cheshire to the M56 then 20 minutes to
Manchester. Loads of bars, restaurants and hotels there. Plenty of shops from
Harvey Nicholls and Zara to Zandra Rhodes and Calvin Klein. You can eat at Burger King and McDonalds to Raymond Blanc and The Living Room or Panacea, the last two a haunt of Premiership footballers, if you like that kind of thing. On the way up, the A49 is a fast 60 limit road with some nice views, a good selection of pubs for some lunch and quite a few passing opportunities. When you get near Whitchurch you can turn East towards Alton Towers.