Mark
I assume you mean the South lakes? - Windermere etc.
From Scarborough head for the M62. Follow that to M61 and then M6 North. Come off at Junction 36 M6 and follow the signs to Windermere.
If you mean Keswick area either proceed as above, but once you hit Windermere, just follow the A592 to Keswick. Alternatively go past junction 36 on the M6 and come of at Junction 40 following the A66 for about an hour to Keswick and the North lakes genererally.
There are shorter routes 'mileage wise' but they tend to take you via the dales - scenic but slower and potentially a bit of a nightmare.
Hope this helps. I do the reverse journey quite often, and it rarerly has problems.