JS, what kind of access area do you have? Is it through the inside floor, or through an outside opening?

If only a small person can enter the area, then one idea with summer coming up would be to hire a neighborhood kid to assist with the installation. Once school's out kids always seem to be looking to make a few bucks for the summer.

My access is from the inside through a small hole. The crawl space exists under an addition that was added to the house so a small hole was made through the basement foundation to provide access. It looks like someone took a hammer and busted up the foundation wall at the top just big enough for me to crawl through and then painted over it when they were done.

Good idea with the neighborhood kid although I think it may be hard to find one willing to do this work ... kinda on the dark and scary side.

JS, if I understand correctly your problem lies with inadequate height in the crawlspace making it impossible to work once inside. One thought I have (kind of hairbrained) would be make a frame that would cover the area, hinge the corners, tack the plastic to the frame. With this done, condense the frame (via the hinges) slide into the opening and then expand to full size. Once this is done maybe you can install some legs to bring the barrier upto the rafters or maybe have the legs already hinged onto the frame. Like I said kind of a crazy idea, but without actually seeing what you're dealing with it's difficult to come up with ideas. Anyway, good luck!