Not sure on hotels. They will be significantly more expensive than if you stay 15 minutes down the freeway in seven hills off of 77. The Rock Hall of Fame is mostly little videos on computers and clothing worn by stars. I had a pass the inaugural year and never went back aside from one event... at which I chose not to do the tour. But I have one cousin very into music who LOVES it.
The Hard Rock really is not within walking distance to the rock hall of fame in colder weather.. though possible. You can get there warmly in the rapid transit though
When are you planning to come? A new aquarium is set to open in January in the flats near all of the action (comedy club, great places to eat, bars).... it is from a company in New Zealand and I believe this is their first North American aquarium. It looks like it will be amazing!
And if you come and stay here, eat at Braza. If you don't mind driving 10-15 minutes go to Melt Bar and Grilled in Lakewood.. they have been on food network a few times... grilled cheese of EVERY kind