In Walden, Thoreau makes very clear that ‘civilization’ is nearby. He made no claims about living in the wilderness.
Who are you going to believe - Thoreau's own book, or what a bunch of college students and environmentalists remember about tough old H.D. Heck, he's almost Jim Bridger's first cousin in their eyes.
By the way, have you ever been to Author's Ridge in Sleepy Hollow Cemetery in Concord?
Thoreau, Nathaniel Hawthorne, Ralph Waldo Emerson, Louisa May Alcott, Broson Alcott, and Harriet Lothrop (who wrote under the nom de plume Margaret Sidney) are all buried in their family plots in an area about the size of my dining room and den combined. Thoreau's headstone either has "H.D" or "H.D.T" on it, that's all.