Hi b0404,
I Cycled Mcbe to Whitby in 1999 as a midsummer treat , and went lancaster ingleton, chapel le dale, hawes, bedale, northallerton,guisebury , whitby, the first part may suit you over the pennines and my ride was 119 miles doable in a long day, but you could split into 2 at leyburn 70 miles fom west coast or at hawes and northallerton for a 3 day ride, but I think you will surprise yourself (if you get some basic fitness and try a 40-50 miler once or twice before hand ) how far you can go in a day, Once the adventure begins even just 12 mph will get you over 70 miles in 6 hrs and around 90 miles in 8 hrs ,
good luck anyway and dont forget to post abt your ride when completed!