Hi all...
just thought i would add some info about cycling in P Ubin...honestly it isnt tht great...am sorry if i am spoiling someone's plan

i cycle regularly in sg and i guess sentosa is definitely better to cycle than Ubin.
Regarding taking ur own bike, it is possible to do tht but avoid taking road bikes as the fun part of cycling in ubin is not on the road but only in the forested area and road bikes don't like tht!!
like said, food is good but not many activities to spend a whole day unless u plan to organize a bbq or atleast go in a group of 4-6. monsoon is not a good time either...
you can possibly go cycling on the roads within SG and halt at a few scenic locations like Mc Ritchie / Kranji dam / Sungei Buloh (via mandai road)... that would be a good 50K depending on where you start/end your trip..
hope it was helpful...
cheers
rishi