Thunderclan camp is located in the heart of their maze-like forest in a small clearing that is hidden by grand oak trees and dense undergrowth that is nearly impossible for any non-Thunderclan cat to navigate through. The camp itself is very clustered and hidden due to the small clearing size and how difficult it is to navigate through their territory. Many sharp bramble thickets are also around the camp, protecting the clan from intruders.
The Highrock, or in this case the Hightree, is a massive oak tree that had collapsed moons ago. A fairly-sized hole in the tree acts as the Leader's den, it's roomy enough for a leader to comfortably sleep with plenty of wiggle-room. Some moss grows on this tree and you wouldn't be surprised to find a bug nest of somesort within the fallen tree.
The rest of the dens are in abandoned burrows that once belonged to foxes, making them big enough for many cats to sleep in them. They are lined with grass and moss to keep them warm in cold weather and to keep them comfy enough for Thunderclanners to actually want to sleep in them, because who wants to sleep on dirt?
The Warrior's den is by far the largest den, obviously since the Warriors makeup the bulk of the clan. In a lower "chamber" is where the apprentices sleep. In a separate burrow furthest from the camps entrance, the Nursery and Elders are here. These two burrows are also closest to the Medicine cat den.
The Medicine Cat is in between the Nursery and Elders burrows and the Hightree. There's small shelves in the burrow to store herbs of all kinds.