I think you've got a good handle on the key requirements.
- You can primitive-camp no closer than 50 yards from trails (marked or unmarked a.k.a. herd-paths), sources of water, and lean-to's. Lots of people overlook the "lean-to" portion and pitch tents far closer than 50 yards (I saw one pitched within 5 yards).
- You can't pitch a tent within a lean-to.
- I know of only two designated camp-sites above 3500 feet: Sno-bird (between Basin and Little Haystack) and Lake Mary-Louise (east of Rocky Peak Ridge).
- In the Eastern High Peaks zone, fires are banned for general camping purposes. However, they are, of course, allowed for emergencies (lost, injured).
DEC's Trail Information for the High Peaks. Updated weekly; describes backcountry conditions and important changes.
DEC Regulations. The ADK Mountain Club's summary of the key camping regulations for the Eastern High Peaks area. Probably the most concise "cheat sheet" available.
The most restricted area in the High Peaks Wilderness Area (HPWA) is the Adirondack Mountain Reserve within the Eastern High Peaks zone. The AMR is private land and, in a nutshell, open to the general public for day-hiking only. More details about hiking in the AMR
can be found here (scroll to bottom for regulations).
The
Eastern High Peaks zone is the most popular half of the HPWA and so it has the most regulations to minimize impacts. The boundary between the Western and Eastern sections runs through Nye, Street, Lost Pond, and MacNaughton mountains.
Bear canisters are mandatory in the Eastern High Peaks zone (Apr-Nov) and the DEC encourages their use elsewhere (i.e. not mandatory elsewhere such as the Dix Wilderness and Giant Wilderness areas).
There's an island of land, approximately 143 acres in size, around Johns Brook Lodge that is called the Johns Brook Primitive Area. A large part of that belongs to the Adirondack Mountain Club. Camping on their property is fee-based and only at the Johns Brook Lodge, lean-to's, or cabins.