Hi -
Previous poster is right - if you are not a keen hiker wanting to get on the hills, then maybe it would be difficult to work out the appeal of Keswick after a couple of days. That said, I love Keswick, but I use it as a base for getting into the hills. You could shave a day off your Lake District stay, and/or use a couple of different bases. I would avoid Windermere, Bowness on Windermere, and Ambleside, which are all very busy as they are on the main road through, and to some people these places ARE the Lake District, believing Windermere is THE lake referred to. (And to be clear, these are Brits!).
Grasmere suffers from a similar problem, but is smaller and worth staying there if you are interested in Wordsworth. Personally, I like Coniston which, although it can be quite busy, is a little removed from the main roads and therefore quieter in general. And it has it's own lake, mountain (The Old Man) a wealth of history, literary and industrial, and some splendid walks.
For your XXX location you could drive east across the country via Hadrian's Wall (which is right next to the road, which uses the Roman engineered military supply road for the most part, because, yes, it is that well engineered) - stops at Housesteads and a little detour to Vindolanda maybe? - and then head north into Northumberland. More history, castles, Holy Island, lots of great beaches to walk (although the weather would need to be really good if you were to swim in the sea!) and in comparison to the Lakes, its big, and empty. Recommend a visit to Cragside near Rothbury too. Accommodation in or near Alnwick/Alnmouth or Bamburgh (huge shoreline castle) perhaps?
Heading north up the coast will take you via Berwick on Tweed across the border and ultimately into Edinburgh. I think there's a choice of routes, either via the coast or through the countryside via Jedburgh or Coldstream, via the model villages of Ford and Ital. Having driven past it on many occasions and being familiar with it only from the weather/shipping forecasts on the radio, I called in at Saint Abbs Head a couple of weeks back. Turns out I was missing a small but pleasant little fishing village (although the big fishing port nearby is Eyemouth a little further south) and a spectacular walk out to the lighthouse perched on rocky cliffs over a moody sea (it wasn't the best weather that day, but you take what you're offered on that front I'm afraid!).
Hope there's maybe some food for thought here, and that your trip is is exactly how you want it. Have a great time!
Ian
