Hi JK,
I did a bit of research. There are some bus-stops near to CVH. There is bus 29 at a bus-stop less than 20 m away from the hotel, which connects to Tampines Interchange. At a bus-stop slightly further away, prob around 50 m, there are bus services 2, 59 and 109. Service 2 connects to quite a number of MRT stations in the east as well as Clarke Quay and Chinatown stations and 59 connects to Bishan. Not too sure about 109. CVH is still accessible, but travelling time will be long. You may want to consider catering a shuttle service for your guests, if it is feasible and the demand is there.