Mary,
I used Expedia to book a room at the HRH for one night in May. When I called to book a room with Universal reservations, they had no rooms available at HRH or RPR for a one night stay. They only had rooms at PBH for rack rate. I checked Expedia, and they had the date I was looking for and the best rate for a single night stay. As far as your personal info you give over the internet, well, it's reasonably safe. Perhaps even safer then using your cc for dinner. As far as Expedia, I have not had a problem with them. And I would not hesitate to use them in the future.