The trail centres in the Lakes are both very short: this is because the Lakes is far and away the best biking in the UK and has an incredible amount of “natural” riding.
Pop into Keswick MTB, BikeTreks (Ambleside), Wheelbase (Staveley) or Evans (Kendal), they all have route maps and guidebooks and the staff will be able to offer advice, you may even be able to hook up with them on a staff ride.
ST Issue 44 has a Lakes Route Guide in it and WMB/MBR often have a Lakes ride in there somewhere too (although the MBR one will almost invariably be the wrong way round…) Have a look on the Bogtrotters website too for the route maps that are linked to the photo albums.
As for where to stay, Ambleside is good and central although it gets VERY busy during holidays. If you’re thinking about May B/H then book NOW and be prepared to pay over the odds for it. Coniston makes a good base too.