Two years ago when my little brother had to travel to Singapore for a business and a few of us grabbed the chance to visit the country for fun, we decided to drive instead since driving would be more economical than flying for a group of 5. Having no experience of driving to the Little Red Dot (well, we travelled by road to Singapore before but that was like 30 years ago lol), we did a few internet searches and asked here and there of what we should know beforehand; yet nothing beats our personal experience. It's actually not as daunting as we thought; instead it was easier than what we have anticipated :D
Recently, we drove to Singapore again and my memory kinds of refreshed again of the 'process' to drive Singapore from Kuala Lumpur, which took about 4-hour journey. I think it's good to share my experience with all and hope it's a good guide to first-timer!
WHAT TO PREPARE BEFORE DRIVING INTO SINGAPORE?
Well-maintained Car
I definitely do not want my car to break down in the middle of highway or in Singapore; I'm sure you are too! So ensure your car is in roadworthy condition by sending your car to workshop for check and service, days before your departure day.
Touch n' Go with Sufficient Credit
Wherever you are travelling from West Malaysia, ensure your TnG has sufficient credit to pay the tolls (i.e. PLUS Highway) to reach Singapore AND back to your home location when you leave Singapore.
It's no fun to queue long at the top-up booth which would be wasting a lot of time. Not only the PLUS highway, there's also a short expressway within JB - Lebuhraya EDL that charges toll fee.