Hello there fellow Queen fan!
I don't konw about elephant sanctuaries in or around Bangkok, as I did not go there for that. However, if you are going to Koh Tao, you might as well drop by Koh Panghan, where you will find a couple of elephant sanctuaries. There is one on the main road a very big road connecting Thong Sala (the pier where the boat leaves you) with Chaloklum. A bit before Chaloklum there is a rather big one. There is also one on the road parallel to the sea, again from Thong Sala to chaloklum quite further on from Haad Yao to Chaloklum. The elephants don't really look that great though. For elephants I would suggest you take a trip to Chiang Mai and from there go to Pai, which has a vibrant artist scene, with musicians from all over, beautiful places to see nature, waterfalls, natural spings (bring your bathing suit) and many many elephant sanctuaries around the village. It's a small village. If you are not into too many creature comforts I would suggest you go and stay at the P.S. Riverside resort, which is by the river, and is gorgeous, day and night. A guy called Nikon has this place and he is the sweetest Thai oldish man you can meet! There's a road just by the school tat will lead you into the resort. 300 Baht per night but public toilet and shower and very quaint little bungalows under the trees! If you like camping you will love this place. Food also very cheap and motorbike the same (all much MUCH cheaper than Koh Tao).
As for Koh Tao, well there aint' much to do in Koh Tao, other than scuba diving, unless you're a drinker and a clubber, in which case you will find a loud, full of english drunksters scene, but also nice if you're into that stuff. There is Lotus bar with music till late, just by the beach at Sairee village and quite good fire shows there and a number of other such bars along the beach. This village really is the place to stay if you're going to Koh Tao. At sairee there is also a yoga centre just off the main road towards the beach, near the centre of the village. Then again there is also Chalok Baan Kao on the other side of the island. This is a small island, one road, 10 minutes from one side of the island to the other by bike. It's quite expensive too. Koh Tao as you may know, is really the place to go scuba diving. It's the cheapest in Thailand and has many many good diving spots you can visit for not too much money, once you've had your first scuba licence. For that, Koh Tao is worth it. For anything else, I would say skip it and visit Koh Panghan. I think you can also do some mountain climbing in Koh Tao but you should check lonely planet for that. One thing to be said for Koh Tao, it has great food!! All kinds. There is pizza Farango, which has got to be the best pizza I've had in Thailand (or in the UK!). Then there's various stools and it also has 2 places for Greek Giros for just 100 baht, the best being in Sairee plaza.
Koh Panghan you may know as the place to go for the full moon parties. Then of course there is the half moon party, the no moon party (I think it's called black moon) and then there is the quarter moon party! Jesus! These take place at one end of the island at Haad Rin. I would suggest staying away from there unless you're a keen clubber. If you want your peace of mind go to the other side. Chaloklum is quite the quiet place and just byeond it there is my paradise beach, it's called coral bay beach, you can see it on the map when you get there. You can also stay at that beach, there are 3 resorts of all prices, some with internet and hot water, rent a bike and travel to other places. This way you will be near the elephants too. Or you could stay at Haad Yao beach, which I think is the best on the island around October to January, but rather touristy. Oh, and if you go there, check out the band Asto Na Pai, they play funky world music and have got some great musicians lined up!! They are usually around Chaloklum and Haad Yao beach. In haad yao beach you will find them at Chocolate Bunglalows just opposite Reefers Divers, I think they have a show every week.
Koh Panghan is also the place to learn about tantric theory and tantric sex, if you're into all that. They also have a lot of yoga and meditation retreats. Check out: http://www.agamayoga.com/
I mean, there is no way you can do all that with just a few days, but I hope I've given you a good place to start with making some decently informed choices.
All the best and enjoy the sunsets at the Gulf!! They are spectacular and different every day!
Btw: when I say sanctuaries I mean places where they keep elephants and people go on rides with them. Some are nicer to the elephants than others. I don't know if that's what you meant?