After making much fuss over adjusting and re-adjusting their packs, they grab their water bottles and embark on their mile and a half "hike", along with thousands of others, on the well-worn stone-dust trails surrounding the "replica" of Thoreau's one-room cabin. Then it's back to the cars to dump the still brand-new backpacks (destined for eBay) and head to the various gift shops and bookstores where they spend hundreds of dollars on knick-knacks to show their friends back home that yes, they made the obligatory pilgrimage to Walden Pond. Then they slap the $6.95 Walden Pond decal on the back of their vehicles, in between OBX (Outer Banks) and MV (Martha's Vineyard), and head back to their city condos and brownstones where they cap off the day with a meal in the North End or maybe over in Cambridge.
Personally, I think Thoreau would be horrified to see the way his pond has been turned into a yuppified ticky-tacky tourist trap.
Now if you want to have a real "Thoreau" experience in the Concord/Carlisle area, there are dozens of great trails in this area that Thoreau walked that are all but forgotten about. One of my favorites is the 10-rod trail that runs from just off Route 4 in Carlisle to the Harvard-owned Estabrook Woods in Concord. I take my dog walking there all the time and I hardly see anybody out there because it's not "touristy" and there is real hiking involved.