Having spent 12 months living and working in South Africa between 2008-2009, I managed to get out and about a few times. During the year I took the train journey of just over an hour from Cape Town to Simons Town. The journey itself is beautiful in most parts, especially around the Kalk Bay and Fish Hoek areas, where the train hugs the coastline and you pass some lovely beaches and scenes. It's safe enough to travel along on this route, even alone, but don't flash your valuables. It's also an incredibly cheap way to travel (even in "first class").
It's the last station of the route, so you can't really miss your stop. There's not a lot at the station itself, with a small ticket office and a shop a short walk - although it's often closed. If you don't fancy the train journey, Simons Town is often included on organized tours to Cape Point, although it'll not be quite so relaxed.
The main attraction of the town is the (Jack-ass) penguin colony. You could walk from the station, but in the heat of the day, along a main road, it's safer to take a local route taxi which again is cheap as chips. There's usually one waiting for the train, which you might have to share with a local or tourists. On the way back, you can call it back from the Boulders restaurant, although it might be a lengthy wait, so call earlier or arrange a pickup time with your driver. The weather can turn down here, so come prepared for rain, wind and sunshine.
Don't expect a big theme park - it's not. A visitors centre with a shop, useful info and photo displays, together with a collection of wooden walkways which meander around the small santurary. These walkways should be fine for all abilities of walker and wheelchairs too. You actually don't have to pay to see the penguins, if you notice a small gate at the top of the car park, a little pathway will give you close-up access to a small number of the penguins. You can also see a breeding area, but don't go in there. They are pretty used to meeting humans, so you can sit next to one and they probably won't even bat an eyelid. It's not expensive to go in to the centre however, and you will get access to lots of useful info and more penguins.
There's loads of opportunity for photos, although at times it can become quite crowded, especially in the summer. You'll see other animals around, usually Dassies (Rock Hyrax).
Apart from the penguins, Simons Town has a museum, visitors centre and some lovely coastline and sandy beach.
I must also mention the Boulders Beach Lodge which is where the taxi stops outside the entrance to the colony. Whilst I haven't stayed here, the restaurant is lovely and serves some great fresh fish of the day, tiger prawns as well as Ostrich steak - amongst other things. It's open for breakfast, lunch and dinner and is very reasonably priced with great service even if you are not a big spender.
A short drive from Cape Town, Simon's Town offers a unique location to view african penguins.
Raised wooden walkways take you from the car park to the visitor's centre. On the way you will see penguins everywhere, hidden in holes in the sand, on the walkway itself, just going about their daily business.
At the visitor's centre there is an excellent display about the penguins, and a video about the life of a city penguin, which was great.
You then descend down to the main penguin beach where literally hundreds of penguins frolic in the waves. The view from the walkways is fantastic, and we took many black and white photos which were very effective. You do not feel intrusive in to the habitat of the penguins, and it is fascinating to see them in the middle of a large city!
It is a unique place, which I would definately recommend to anyone going to Cape Town. It is on the way to Cape Point, so worth stopping off if you are heading that way.