If you plan to take the Airport bus, you need at least 10 to 20 min walk depending on the amount of luggage you have. No matter if you take the airport bus to the hotel or back, there are some ways to take. I didn't see any options on Expedia to book a shuttle bus to and from the airport though.
We had a booking for a family room on the 12th, our plane arrived 23:50 so when arrived it was almost 2 am on the 13th. We had a booking for the bunk bed for the 13th to 16th. I ask if can upgrade free of charge, they gave me the upgrade. We didn't have to check out and check back in. I give them give stars for this.
I didn't eat in the hotel but they do have a buffet though. If they offer a free buffet for one day, it would of been great.
This is my second time staying in Charterhouse.
The last night I didn't put the sign outside to clean the room unfortunately some body flip the sign to say don't disturb. Did leave a note since we are in travel mode so didn't come back early. This is why gave them 4 stars.
If staying at bunk bed room, make sure when taking shower your back should not be facing the door or the water will leak out. It seems they didn't seal it tightly.
Overall experience was good. Don't take the airport MTR as you will be changing lines. Take the airport bus is the best way to go.