Everything worked like clockwork on our two-day excursion. The van and our guide, Robert, picked us up right on time at our hotel to start our trip. We wanted to see the less touristy parts of the Great Wall and sleep overnight on the Wall. We started at a very rustic and low-profile entry point and hiked the Jinshanling section of the Wall (about 120 kilometers from Beijing). The scenery and experience rival anything I have ever seen, and we only saw 6 tourists during the entire trip. Fiona was great on making arrangements over the internet and everything occurred just as promised. Robert was a terrific guide who provided just the right balance of info and silence so we could enjoy the experience. Robert speaks excellent English and is very friendly and knowledgeable. We had a spacious van pick us up at the door of our hotel and get us to and from our destination. Our driver, Mr. Tong, was a very responsible fellow. I would highly recommend visiting the Jinshaling section of the Wall (vs. the closer and more touristy spot, Badaling), and would also highly recommend Great Wall Hiking to take you there.
A word of warning about the overnight stay on the Wall. The latrine is a bucket (I knew this going in, and only choice, so not complaining, but be aware of this.) I was not confident that the sleeping bags/pillows had been cleaned (in fact, I am pretty sure they were not). The whole sleeping arrangement did not seem very clean to me, which was disappointing. I can say I slept on the Great Wall, and I don't require luxury, but it was a bit rougher than I expected. This is really my only complaint about the outing. To be safe, I would bring a sleeping bag liner and a cover for the pillow.