We stayed on the QM before our Carnival Splendor cruise in Oct 2009. She was also showing her age and needed a refurb. I know she has come under different management since them. Food was good but not fabulous - though we didn't do the brunch which seemed to bring people in droves. The highlight of our stay was watching Splendor arrive in the dark about 6 or 6:30 (our bodies were still on EST so this was not a problem.)
The staterooms used by the hotel are probably much like they were when she last sailed with a few modern amenities added (TV, iPod dock.) We did the self-guided tour but not the ghost tour.
Was very handy sailing Carnival. We walked over to do early check-in, went back for some relaxing time on deck and then walked back to the terminal at our assigned time.
A Bad Day At Sea [with power] Always Beats A Good Day At Work
Alaska 2014 - haven't picked a cruise yet
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, Caribbean 2013