If you are in Bangkok and you've toured the city by bike, loved it and wanna do it again, I suggest going to Ayutthaya.
We missed the quick train to Ayutthaya. We had to take the ordinary train. Translation: No airconditioning. Ordinary train costs 15THB for foreigners and free for locals. The airconditioned train cost 300THB as I remember. Glad we took the ordinary train cause I haven't experienced riding into one. As I told Luke, I've always wanted to stick my head out of a moving train. I did that on our way back. I was happy then.
Below is the boat that we took to cross the river. It cost 4THB.
Don't worry about renting bikes. It's everywhere on the pier. I think this costed us a little over 100THB to rent for the whole day.
Armed with a travel book and Luke's compass watch, we travelled to Ayutthaya by bike. Loved the ruins and temples!