You said it pyrex. Also, as for walking at night, I would rather risk doing it all at night then at day. The likleyhood of a 5-0 chopper seeing you is pretty slim. I live in a pretty good sized city and I honostly don't remember the last time I saw a chopper randomly looking for crooks. BUT, cops do look at people driving around at 3am a little suspiciously anyway.
I am more of the guerella mentality. I would drive out there during the day (a time when people are least likely to be around) have my supplies repacked into dark sacs and placed off trail (not too far though) in the brush, cover it w/a camo tarp or throw some debris on it, and come back out at night. Either way if you plan on doing a "in the tree grow" your looking at ALOT of supplies. What I would do? Start them in the dark colored hanging pots at house and wait till they get a set of leaves, and gather your ropes and gear in a backpak. That way when the time comes to set it all up you can just get ready and go out one night and set it up.
Most importantly like everyone else has said be smart, don't do this in a high risk area. If you are worried about people seeing you in the process chances are its not a good location. ALSO think about how you are going to tote the H2O and how often. Good Luck