I think you're right to go from Watendlath, Ken. There is a boggy stretch but it's crossed by stepping stones. Afterwards you may not want to go back the same way, so I suggest Birkett's Leap - it's on the Watendlath-Rosthwaite path and offers great views all the way up Borrowdale. You may have been there on your way down from King's How, though it does sound like you used one of the less-touristy paths!
You used "chocolate box" earlier, last year I thought Dock Tarn was "chocolate box plus Kendal mint cake plus shortbread biscuits". Good luck ( grrrrr
)
John