The Rock is Gibraltar and, unless you are able and interested in exploring the rock, there is little point in visiting Gibraltar. If you have the time and energy, it is best done on foot; otherwise there are cable car and taxi options. The latter may seem surprising but most of the walkways on the rock are, in fact, narrow roadways and the taxis are a nuisance to walkers.
The upper parts of the rock are a designated nature reserve and an entrance charge is payable. There are two entrance points: Moorish Castle, above the town at the north end of the rock; and Jews Gate at the south end of the rock. The former can be reached by a long series of steps from the town; or by bus 1, which stops just short of the park entrance. The latter can be reached by bus 2, alighting at the Rock Hotel; or by the less frequent bus 7, which takes you closer but still terminates some way short of the park entrance. Which entrance you choose will be determined, to a large extent, by the attractions you wish to visit. If you are there for a couple of days, it is worth splitting your time between the attractions at each end of the rock.
The basic ‘walkers’ ticket cost 5 euros per person per day; an additional 8 euros will upgrade this to an ‘attractions’ ticket, providing access to the Great Siege Tunnels and St Michael’s Caves (both highly recommended) and a number of lesser attractions. Alternatively, you can pay an additional 8 euros to visit the Second World War tunnels, which need to be pre-booked by telephone. It will cost 21 euros to visit everything in one day, or 26 euros to split the visits over two days (visiting all the ‘attractions’ on one day and the WWII tunnels on the other).
There are two cafes on the rock: at the cable car top station, and at St Michael’s cafe on the walk up from Jews Gate. It is also possible to buy bottled water from a vending machine just inside the Great Siege Tunnels. Don’t dismiss warnings about the macaques (apes); they will attempt to steal food and anything else that you may be carrying, and are quite adept at unbuckling back packs (I speak from experience). Allow a full day for your visit – preferably two if you wish to see everything – and start straight after breakfast to tackle the ascent whilst the rock provides some shade.