If the adventure is still sailing at 10 PM and you are there for early check in, then yes, you'll have time to go site seeing. You may just want to check in your bags and have your cab wait for you rather than fully checking in. You can be back around 5 pm and complete your check in then. Saves you from waiting in a long line up.
More than 300 days at sea so far with many more to come. (Actually more - one of these days I'll count them properly.)
Celebrity Solstice - Feb. 21/15 (moved out a year due to illness)
42 cruises - too many to list however cruiselines are in no particular order:
and some unknown tub
Yes, I'm a Royal Chump and proud of it.