Upvote:1
Here are the options:
Contact a tour agency or a hotel in Medan. Contact them by phone, emails are things of another world for many people in Sumatra. Mind that locals are not very used to plan things very much early before the d day.
Best thing is to contact 3 or 4 agencies and bargain as little.
You can also contact Mr Dermawan, he is quite famous in Singkil for organizing journeys & tours for tourists. He seems like a nice person. As pointed out in this question's comments travel.stackexchange.com/q/48622/9395 Regarding Dermawan, the phone number you provided is out of date, this is the correct one: +62 82166457040. Dermawan Email is [email protected], He is a reliable man. But in Sumatra, nobody is reliable enough to keep a phone number more than a few months.
Shared taxis are nice, they are modern, have AC (put your gloves on), but they often get overpacked with passengers, bags and even delivery boxes. Yes, those taxis also deliver packages so it can get a bit out of hand. Same thing goes for picking up passengers, been on a Singkil-Medan journey where the driver did an extra 2h drive (in some horrible non tarmac country side roads) to pick up 2 passengers. Sometimes it's simply much better to charter a whole taxi for a little bit extra.
Upvote:3
As a general rule, if you are in Medan, Go to Mejid Raya (Angkot Mr X) then ask any travel agent
In the particular case of Singkil, contact Mr Dermawan (+62 82166457040). He is the manager of "pulau baniak Taxi" and one of the most reliable person in north Sumatra. As far as I know, the price is 140k rupiah per person
There are also minibuses a bit cheaper (100k) but it does not worth the inconvenience. In case of flood, Dermawan would commission another taxi on the other side of the water while the minibus service will tell you to make the last 80 kilometer on foot.