Loved Singapore. Lived there for 3 years back in the 60's and also stayed on our way to NZ a few years ago.
We have never been to Raffles but they have a sister hotel in Penang, The Eastern and Oriental which is a similar standard. We had lunch and afternoon tea there several times on our visits to SE Asia over the last 11 years.
We didn't visit many sights in Singapore as we tended to just wander around eating, drinking and sleeping to get over jag lag. But there is the Botanical Gardens which I visited in the 60,s which was was wonderful, even to a kid. Be warned it is baking hot. You need to wear pure cotton, linen or silk Hope you enjoy your stay, just don't try to do to much, save your energy for NZ.