I'm with plumber- there's so much good riding in that area you don't have to restrict yourself to the trail centres. There's a good ride around Claife Heights which is on the other side of Windermere. There's also a fab ride around Loughrigg Terrace. Bike Treks in Ambleside will sell you lots of maps with good routes on them.
Also try Chesters in Skelwith Bridge for afternoon tea- it's the best tea shop by miles.
Solar- have you tried Wheelwrights for accommodation? They specialist in places in Ambleside, the Langdales and the surrpuinding area. We stayed in a lovely cottage in Little Langdale and rode from the door on one day and a short drive to another start point the next.