See my review of the Alcazaba (dated 4th June 2013) for more information about the Gibralfaro, as these two fortresses are literally linked to one another as part of the same monument. Both places are wheelchair friendly in many areas.
A note: besides the Tourist hop-on, hop-off Bus with a service each 20 - 30 minutes around the sights of Málaga, there is also a local bus (no. 35) running between the port and the Gibralfaro.
The Tourist Bus takes a hour and a half approximately to circulate all the stops around Málaga
Remember that, as with many museums, these places are closed on Mondays.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.