There may be enough of Kendal in the Kendal and Morecambe seat for Farron to come through in what would be a three-way marginal. I think you have to split Kendal at least two ways if not three.
Its not clear from the mpa because the colours are too close, but I did split a bit of Kendal off into the Valleys of Eden & Lune seat. Just under 20,000 voters in Kendal and about 26,000 in total from his constituency against about 50,000 from Morecambe & Lunesdale. You're right it would probably be pretty close three ways though
I was expecting this sort of arrangement to produce a safe Conservative seat, but looking at last year's council elections in the wards concerned, I actually get the following:
SNP - 32.0% Con - 31.8% Lab - 25.2% LD - 11.0%
Which means that Labour would probably find a way to win it in a Westminster election. The problem is that you can't get around the Pentlands by road without including some areas that are pretty awful for the Conservatives.