We made the trip out to Denver from The Carolinas last Thanksgiving. Between the flying, renting a car, room, and of course testing, it was a pretty penny; HOWEVER, it was worth every penny.
They will meet with you over the phone or Skype ahead of your visit and answer many questions ahead of the trip. They can and will advise which tests to give, and of course you can take them up on their recommendations or not. After the two or three day visit (in our case about 4 hours a day for three), you'll get an extensive report and consultation.
As many have attested already, your kid will probably love the experience. Mine wants to return next year.
We had ours tested locally ahead of time. When the tester didn't "see any reason to do extended tests", we realized most testers in our area either don't understand ceilings, or don't really see the point in finding one.
My wife and I are in a discussion with her current school over some of comments in the report Dr. Silverman and Dr. Miller wrote. The report is probably the most extensive profile her school administrators have ever seen, and has become a learning experience for them aswell.
Feel free to PM me if any question
