Hi @garth welcome to the community, I hope your stay here is pleasant 
I think the idea of the bags in the tree is ingenious, even I would add a usb solar panel in case the weather gets rough and you can not descend ^^
Also some 18650 batteries already charged wouldn’t be a bad idea
I don’t have a board to check but you should do all that just with the python client without using a cellphone
Check this post you might be interested
And a wiki about antennas