I'm all for a bit of a logistical challenge - been trying to grow outdoors here for years !! (first successful year - still to be finally documented). - but unless there's a real reason you can't grow indoors (I reckon I can be self sufficient 1g/day doing three grows/year in a 1/2 wardrobe space), I'm just coming up to the end of year one but I know It's do-able (or is that doobieable).
But outdoors if you are climatically challenged means budrot and frequent (if glancing) checks across guerrilla sites as it gets close to harvest. If legality is an issue and tree concealment a potential solution, I would consider this, it's much easier to persuade a jury you were foraging for woodland plants/fungi (explaining some tools n crap in the rucksack) and stumbled across somone elses clearing plot - than being caught up a tree at the time. If your area is foot path'd consider also that kids love tree-houses and it will get spotted by some wee brat out walking (probably under duress) the family dog.
Clearings are good spots - hunt them out away from footpaths - a lot of commercially planted woodlands have built in circular clearings which will be utilised later for harvesting access but remain off the paths - google maps satellite and GPS can be your friend in finding them.
If , on the other hand, you are an experienced rope climber, have the right site (not to dense woodlands) - and the will and the way to put in all the effort (as some famous explorers might have said - it was the last few feet that were the most satisfying if painful)...
Good Luck