Where to start? You should have no problem occupying yourself for 5 days, but it depends what interests you? History, shopping, nightlife, tourist attractions, simply browsing round?
One thing I would advise is getting a pre-paid payment card for the buses and metro. Singapore has world class integrated public transport and you can get pretty much anywhere on the island quickly and cheaply with no more than a couple of changes.
We have done the KL by train with our daughters school. One bit of advice...make sure you pay for their version of first class, that way you get a sleeper. I recall it's a night departure and not much to see. The railway runs on an old narrow guage (by North American standards) and it can be a rough ride! You will get a small bowl of rice and chicken and a drink with the price of the ticket. The daytime ride back is great, but no sleeper, the sights on the way back are quite good, lots of jungle! I like train rides personally so it was a trip worth taking. If you know either KL or Singapore there is a major diff between the cities. As for what to do in Singapore...Eat and shop seems to be why they want you to visit! Sentosa is fine to visit. Take lots of $$$. The comment about the cabs and transit system rings true, very easy and safe. Enjoy! LC
did train ride from KL to Singapore 3 years ago---local train, daytime, 1st class---came into heavy showers, train stopped until over---very interesting journey (eg 10km away from KL 3rd world!!)---take enough food and drinks with you---enjoy
For shopping get yourself down to Orchard Street, if you're looking for electronics take a wander to Sim Lim Square down by Rochor, generally the higher up you go the better the bargain you can get.
Can thoroughly recommend Jumbo restaurant as a seafood place the pepper crab and the chilli garlic crab are a must. However, the best advice is to get a pre-paid card for the underground [the MRT], it's dead cheap, clean, rapid, goes pretty much every where, and it will save you having to work out where you are going each time, plus you can top the card up & they will last for about 12 months if you're heading back at any time.
All cabs are government regulated, so the fares are the same regardless of what cab you get & they pretty much all take credit cards as well, but just ask before you start off as if the card machine won't work you need to pay cash on the nail.
If u r coming alone, OT will blow ur mind. And if you want some local taste, go to geylang.
For good clean fun, u could try little india and chinatown. Little India has this shopping mall Mustafa which has almost everything at very cheap prices. And it's also 24 hrs. Also try d food. And if u r going to Sentosa, check out the casinos and the universal studios. I heard they by end of this week.