living in SG for over 2 yrs now we found Tioman the best doable weekend getaway - but we like diving which is outstanding as well as the snorkelling. We normally stay on (budget) ABC Beach which is simple and does not really feel touristy as there are no big crowds or package tours - a good backerpacker mood there is and a package of 3 beers go for RM 10 only.
Probably the best chalets with seaview are here (from RM70):
http://www.geocities.com/bamboosu/
What we usually do is take a taxi from Singapore to Mersing in the evening - On Fri night that can cost as much as S$120,-- which includes 2 hours of traffic jam at the border. At any other time it should be cheaper and far less time consuming. NB from JB to Mersing by taxi will cost between RM 130-RM 180 depending the time. From JB to Mersing jetty takes 2 hours + 15 minutes. In Mersing there are decent rooms for RM 55 per night (fe Embassy Hotel).
The ferry to Tioman leaves at 7.30am and takes 2-2,5 hours incl the inevitable delays and depending which beach you want to be dropped.
We found Bintan Resort area actually more an extension of Singapore, with prices of food and alcohol on (mid to upmarket) Singapore level. Paying US$14 (menus are in dollar)for a coctail is quite normal here. It's quite an unnatural, fully designed, landscaped and fenced off part of the Island, where no locals live apart from servants. I won't send my oversees friends there unless they want to be on a spa package and have big money to spend.
An alternative may be Bali, the DIRECT flights with Lion air can be had at around S$200 per person and the plane almost arrives at the beach! The flights have excellent timings as well!
hope this helps.