Absolutely, to travel from India to Singapore by Road is possible. Starting from India the route will be from India-Myanmar-Thailand-Singapore via AH2.
Delhi--Siliguri--Guwahati--Imphal--Monywa(Myanmar) via AH1 and Monywa-Kalaywa Highway. From Monywa to Thailand via Yangon-Mandalay expressway or Yangon-Naypyitaw-Mandalay expressway. The total distance is around 1,326 km.
· Now head for Malaysia from Thailand via AH2 which carries the total distance of 1,701 km.
· And the last rides remain that will make you reach your destination that is Singapore from Thailand via Lebuhraya Utara-Selatan expressway2.