Originally Posted by
Scifience
As moondog says, there's absolutely no reason to hire a tour guide for a day trip to the Great Wall from Beijing, as nowhere within typical day trip distance is really dangerous or remote enough to warrant one; this is very much on the beaten path.
I don't know. I've been on a few hikes with Beijing Hikers that were borderline scary. Also, a long time ago, I was at Huanghua Cheng with a friend and a (rapidly) falling rock, accidentally dislodged by another hiker, came within 6 inches of his head.
That having been said, I still enjoy some of the more adventurous Great Wall spots near Beijing. In fact, I've recently started replicating (level 3 and below) Beijing Hikers' hikes on my own (they post maps/directions on their web site).
I would recommend heading for Mutianyu; it's less crowded and less of a tourist trap than Badaling. Take bus 936 from Beijing Dongzhimen bus station (there's two early-morning departures last I checked, at 0730 and 0830), and return in the afternoon. The bus should come in under ¥50 per person altogether; entrance is another ¥50 or so.
With 6 people, I think a van makes perfect sense.... probably 150-200 per person.