I haven't explored the Cumbria coast yet, but I don't think it'll be a patch on Scotland's west coast. Crossing over the M6 from the Lakes, you've got the roads over the north Pennines, Hartside cafe etc. From Alston down to Middleton is a cracking ride too. If you take a full day, you can go all the way down through Hawes to Settle, then come back up via the Lakes. About 200 miles, more good roads.
Cockermouth to Penrith is the A66. Not great, much of it is boring dual carriageway, but you do get some good views of Blencathra as you go from east to west. I only really use it as a way to get out to the turn off for Ullswater, well worth following that all the way through Glenridding and Patterdale, and on up over the Kirkstone Pass.
Another biker cafe is the Filling Station in Keswick, just off the A66.