The area is access sensitive!
CapeNature Areas (Public land). Daily R60, weekly R200 and monthly R750 permits for climbing. Permits can be bought online through climbing.co.za but it is recommended that you buy them on site at for example De Pakhuys, Traveller's Rest or Clan Williams tourist office. The permits are not limited so they will not run out.
Park to the Pass parking. Take the sandy road, walk it for about 800 meters, take a turn at the cairns to the right. Walk this path for 400 meters, take a path to the left (up to the fortress). Walk uphill along a cairned path for another 500 meters and you'll arrive to the Fortress Boulder.
Approach is 1700-1800 meters in total, and that should equal to 25-35mins.
There are a couple of boulders by the path.