I checked out this Bangkok oasis today. Will post some pics soon.
Of several Bangkokians I asked about it, only one had even heard of it, which seems ridiculous because it is a jungle smack bang in the centre of bangkok, only about 3-4 kilometres from sukhumvit and sathorn.
Anyway, we caught a taxi from silom to narathiwat, then rama3, then half way over the new double bridge that goes to samrong before heading onto the island (peninsula actually). Its about 5km by 3km in size, and is very sparsely populated, with perhaps 5000 residents.
Once you get to the north of the island, things get really quiet. There are small country lanes remiscent of koh chang if it were flat, and raised concrete sois which are only suitable for walking and bikes running through the jungle. Some of the houses on these sois are amazing because of their tranquility, and yet if you were to stand on the roof you would see the skyscrapers of Bangkok not much more than a stone's throw away.
We ended up at a beautiful park called sri nakhorn khuan kan, which in my opinion in the nicest, most natural, and quietest park in Bangkok (no traffic noise like lumpini and jj, and no noisy fucking radio speakers every 20 metres like Rama IX).
Ten minutes walk from the park is a pier on the river. A 5 baht, 5 minutes trip had us arriving at wat klong toei nauk, very close to lotus rama IV, and back in the noise and hustle & bustle.
It is an amazing place and well spending a day on seeing. I will be back (with my mountain bike)