Singkil is in southern Aceh.
Apparently few locals have crocodiles in the gardens. If you're lucky, you might spot one in the river.
Island hotel - 5 mins walk to both ferry and cargo boat pier. Non aircon room 100000 IRD (June 2015)
Sonia - located 50m from cargo boat pier. Basic accommodation with shared bathroom. 30000 IRD (June 2015)
You have to travel first to Subulussalam, there you can change a bus.
See Banyak Islands for information about ferry.