Hi Mate
If your thinking of meeting and taking a few Thai guys back to your hotel, I suggest you take this in to account when selecting a place to stay, my first time in Bangkok some time ago I stayed at the Holiday Inn - Silon, after the taxi journey back from the main gay areas it was a nightmare "smuggling" a friend in or paying the joiner fee when ever we were caught!
I would suggest you consider a more "gay friendly" hotel such as Tartawan Place or the Rose hotel, both are excelent, depending on what you want, I use the Rose Hotel more now as whilst the rooms are a bit smaller, it is cheaper and I love their pool! Both hotels are a couple of minuites walk from the main gay bar areas at night and you will have no problens taking any new "Thai friend" back, providing he has ID and is over 18, which makes sense. During the day from either hotel easy to walk over to Lumpini Park and relax (& if you like more muscular guys see them working out in the open air gym!) or simple to get arround Bangkok as the nearest Sky train at station at Sala Daeng or the underground is only a short walk. I would also suggest during the day to try the tourist river boat, only a couple of sky train stops away, amazing value and a great way to see the city and stop off at some of the main tourist attractions from the river. It is also only about a 40 min gentle walk up the the main big shopping areas you mentioned, or easy by Sky train.
Hope this is of help and have a great visit!