Hi Stephen,
Sounds like a really good idea. There are plenty of people who can better advise you regarding places to pitch up (e.g. April & Beefy).
As far as must do places to see/walk - well you will be spoilt for choice everyone has their favourites and heading to both the ones you mention is the right thing to do.
I would recommend Great Gable, you can follow the traverse around it's Wasdale face and that is a view to behold (from the Westmoreland Cairn). This could be reached from Borrowdale/Seathwaite up to Styhead tarn. From the tarn you are in the centre of an area where you can easily get to Great Gable or Great End (to different hills/mountains) then across to the Scafell massif.
Sorry, I could go on for ever and there are countless places equally as good as well as some of the minor peaks which should't be missed just because of their lowly height. Langdale Valley being another great place to centre yourself - with easy access to the above places as well as the Pikes around that valley.
Incidentally, I follow your posts and really appreciate the trouble you put in to show off your 'stamping ground' to those of us that haven't ventured over there yet.
I am sure you'll enjoy wherever you go.
PS- visit David Hall's website for plenty of inspiration and route recommendations -
www.davidhalllakedistrictwalks.co.uk