"I have trekking poles and intend to practice setting it up as hammock and with the poles before heading into the wilderness."

You mean setting it up as a tarp?? Trekking poles won't support that hammock, but it makes a nice tarp using the poles if no trees are around.

Anyway, I've been a avid user of Hennessy's (i have two) since they started making them and one of the reasons why is that I DON'T feel all closed up. You can see out and exiting the things is by simply falling out the bottom slit in one easy motion. From the outside it looks like a cow giving birth.... <img src="/forums/images/graemlins/grin.gif" alt="" /> Probably the creepiest thing I had to get over, albeit quickly, was the feeling of being suspended and sleeping in mid-air, by two thin ropes. You'll enjoy not being cocooned in a mummy bag, using it as a quilt instead. I never put out the rain fly unless it's wet or really windy and the bug netting stops a lot of wind, which give a more open feeling.
My wife had the same claustrophobic misgivings as you but after her fist night in the hammock, I had a hard time getting her out the next morning. You will sleep very well! We use only a Ridgerest pad for the inside and a mylar sheet to block wind on the outside...nice and warm.

As others have mentioned, there are some nice tarps out there too. There's just something elegant about being able to suspend and be inside your shelter, in one minute, with absolutely no concerns about ground levelness or rocks/sticks, as in a hammock.

Before the Hennessey, I used an open homemade hammock made from 4 yards of ripstop. I still use it as a loaner. You lay in it the same way as a Hennesey but the bug net is separate. You can duplicate that hammock using a queen/king size bed sheet tied with rope using sheet bends on the ends....for a trial run, assuming you haven't bought the Hennesey yet. One advantage of an open hammock is that you can enter/exit from all sides. I still prefer the Hennessy though, for other reasons.

Car camping and day hikes.....ain't nothin' wrong with that, what-so-ever! Makes for nice trips!