Welcome to the forum Chickie!
Three Centuries on Winnipesaukee, by Paul Blaisdell, has this photo from 1923 that shows the Governor Endicott in for repairs at Lakeport near the end of her lake career. There are a couple other stories about her in this book along with reference of Winnipesaukee Transportation Co. When I have more time, perhaps I can look into this further for you.
A quick forum search came up with a couple forum threads you may be interested in.
Excerpt from Three Centuries on Winnipesaukee and Other Historical Stuff
Governor Endicott Question
Let us know if you find more before we do. Good luck!
Be sure to search
PhotoPost too.
Farewell Old Mount Washington, by Edward H. Blackstone, has a couple of photos, which I could scan at a later time. Upon a quick reference, it confirms the Lake Winnipesaukee Transportation Company had their base of operations in Lakeport.