The only place I`ve been on holiday in the UK is the Isles of Scilly. i`ve been to lots of walking areas (Northumberland, Scotland, Lakes etc) but I wouldn`t go anywhere in the UK for a holiday as such. I`ve got friends with a house in the Isle of Man and they say I can go there anytime but I haven`t got around to it yet.
Furthest part I've been to is Edinburgh (which I loved), would like to go to the Lake District at some point and the same as you, Northumberland (thanks to the TV series Vera). In Aug we'll be driving up to Scotland, getting the ferry to Larne, then off to Giants Causeway, then down to Belfast for the Titanic Exhibition, then on to Dublin for a few days.
I would love to go to Liverpool - I know it is not far away - but am awaiting for the oul vertigo to eventually go away before I travel on plane. Been to Isle of Man - great touristy place years ago - I would say nothing in it now. Blackpool not great in my opinion of course.
Aviemore skiing is the furthest north I have been and Southampton is the furthest South. I have been to many places inbetween. I have been to N.Ireland but never been to Wales. I would love to see parts of Wales, Devon, Cornwall and Somerset.
The furthest I've driven for a holiday is from Kent to the Lake District. I've also been to Edinburgh and the Trossachs from Dorset but as i flew it doesn't really count. I'd like to go to the Scilly Isles.
Northumberland is indeed beautiful. Have been all the way up to the top of Scotland several times (from here in the south) - places for me, I don't know Lincolnshire that well and also would love to go back to North and West Northern Ireland, Isle of Wight too - never been there.
For rocky - I grew up in the Lakes (and down here) - you should also look at the east side of the M6 (Appleby/Kirkby Lonsdale - places like Hawes, Leyburn, Kirkby Stephen, and all in between - beautiful countryside and much quieter than the Lakes - James Heriot, "All Creatures Great & Small" countryside.....
Mainland Scotland I should have said....also was briefly in Shetland on way to oil platform in the ninian field..north sea.....would like to do the channel islands !
Warning, murray; give a big detour to Land's End if you come down this way, and Newquay.....I have been to John O'Groats too and that isn't too bad, well in comparison to the commercialisation of the sites.
Have you been to the other side, i.e. Cape Wrath, there is some beautiful coastscapes along there, and lovely countryside around Durness and Tongue.
New Forest to John o' groats and points west.
Sandy, you have to do El Camino before the highland way. I'll leave a cold beer on my garden wall for you.