For practical purposes in CA there is a huge difference between being on land that the feds patrol like National Parks, National Forests and BLM etc. If you get caught on any of those lands with marijuana your CA medical license it totally invalid.

You may not have noticed that I said "I feel pretty legal" not that I am legal. Your physicians statement is just one argument in your favor if you get busted by a CA agency as opposed to a fed agency. You can definitely get busted for marijuana by federal agents anywhere in the United Stated or its posessions. However they only make an occasional bust outside their "territiory" to try to scare folks from going all out. They arrested a woman in Mendocino Co simply for obtaining a 99 plant permit and posessing the 99 plants permitted. A clear example of the feds "sending a mesage". Many other folks have applied for the same permit without being hassled at all.

Total legalization I predict is inevitable. The last two presidents have been admitted stoners and or alchoholics and look where it got them.