For the HR HK, get off the Airport Express at Kowloon and shuttle or taxi to the hotel. HR HK is close to the MTR, so you take that to HK Island and get off at Wan Chai, or walk/taxi from Admirality if you don't want to transfer. It seems to be a long walk from Wan Chai and the taxi's are cheap. I did a taxi from the Regal Kowloon to GH HK and it wasn't bad at all. Something around US$11 if I remember.
For the GH HK, take the AE to HK and shuttle (they usualy stop the free shuttle before I arrive,) or taxi (about US$4 and more convenient as the shuttle drops you at the entrance of the convention center, between the GH and Ren. A pain to carry luggage up stairs or around the block to checkin. Taxi is the way to go here.)
The last couple of times I was in HKG, the AE ticket sellers were checking for CX boarding passes for the half price tickets. They used to let anyone use the discount coupons (printed off the internet site for CX specials.) I think the most recent coupon expires like March.