I've seen inquiries on this forum about visiting the Lake District using public transportation, and I don't recall any of the replies mentioning boat cruises that connect with bus and train routes. Some also connect with walking paths (hiking trails. For anyone interested, here's a handy page.
"There are public boat services on four of the main Lake District lakes; Windermere, Derwent Water, Ullswater and Coniston Water. They all provide wonderful scenic boat cruises, often used for pleasure but most also connect with buses or trains allowing onward travel across the area." http://www.lakedistrictonboard.com/boat-attractions.html