Originally Posted by
bacon_grease
The fastest would probably be a length of webbing with a quick connect (dutch clip or carabiner) at one end and passed through a pair of descender rings tied to the hammock.
Get to the site, wrap the webbing and quick connect it in place around a tree, repeat on the other end, then yank on the bitter end of the two straps to the appropriate tension and you're done.
When you're done, let out the webbing to full length, unclip and stuff.
This does beg the question... Why are you looking to speed up hammock hanging and how fast do you really need it to be?