Last year in September I went by big bus ( 4 hrs) from PInang Baris bus station in Medan to Bukit Lawang.
Pinang Baris is a long way ( about 30 minute trip early am, maybe longer later in the day) from the main backpacker accomodation area around the big mosque.
Beaware you will have to wait for the bus to fill up before it leaves
Alternatively you can get a mini bus at an unmarked terminal about 1 km away from Pinang Baris and the guy who drives the green bus- see my photos ( leaves about 7am) can get you to Nora's in the village in 2.5 hrs.
( I found all about this after spending 5 weeks going back and forwards to Bukit Lawang from Medan).
Whilst in Bukit Lawang I arranged for an ojek (motor and rider) to take me the 2 hrs down to Tangkahan. Fantastic trip by motor bike over the roughest of roads, but what a hell of an adventure- I loved it.
I had the freedom to stop the bike and take photos along the way as well.
Make sure you get Nora's brother Kevin to organise the motor guy- he lives down the road from Nora's Homestay in the village of Gotong Royong 5 minutes from Bukit Lawang by becak.
It is definitely a trip where you need an experience bike rider to take you.
On returning to Bukit Lawang a guy named Darwis from Tangkahan took me back to B.L. and he was a safe careful rider as well.
Leave your big backpack in Bukit Lawang at one of the guest houses- I know for sure Nora's will hold it free of charge for you, probably other guest houses will also so.
In Tangakahan make sure you visit the elephants and get involved in giving them a scrub in the river- great experience.
There are I think now three places to stay in Tangakahan, namely Bamboo River, Jungle Lodge where I stayed and loved it- stayed in the small room on the edge of the river bank 20 metres up and Mega ( speaks very good English)one of the guides had built two small bungalows when I was there- so I guess they would be open by now.
My advice about length of stay is about 5 days- it is really worth it. Such a paradise in the jungle- you have to cross a low river by small boat so it is quite an adventure compared to most other places.
There are lots of things to do like doing an elephant trek through the jungle, tubing down the river which I did and you can also go trekking by foot in the jungle.
I even went to the local village with my guide Darwin and visited the local rubber market.
Sylvia the owner- not sure if they will still be there or in Germany took me river trekking and I did things like swim over small rapids, lay in the hot springs opposite Jungle Lodge and get massaged by a small waterfall around the corner. See my pictures.
Unfortunately I had to give the jungle trekking a miss because I fell down a small hole whilst photographing the beautiful bedroom at Jungle Inn in Bukit Lawang and really hurt my foot.
Here are some of my photographs of Tangakhan.
Plus my photos of Bukit Lawang from my 2006 trip
For Ketembe you will need to return to Medan and get a bus from Padang Bulan- get a ankot- small city bus No. 41 ? in Jalan Juanda down to the bus station.
The trip to Ketembe takes you to Kutacane(7 hr bus trip) via the very cool area of Brestagi and from there you will need to get a local bus to Kutacane( 1 hr) before 5 pm.
If you tend to get bus sick,suggest you take some ginger tablets with you- the road is very winding on the way to Brestagi.
Ginger is wonderful and does not drug you out like the other motion sickness tablets.
Here are my photos of Ketembe
If you get to Kutacane too late to get the bus to Ketembe don't worry because you can stay in Kutacane for the night.
I chose to stay the night so I could give travellers this information.
I stayed at the Maroon Hotel- not fantastic- but o.k. cost 60,000/night.
Another hotel RedApe used to suggest on Thorn tree is so expensive now- over 100,000 rupiah- too much for backpacker me.
The local bus goes along the street where all the accomodation is in Ketembe so you just tell the driver where you want to stop.
i.e Pak Mus Guest House, Sadar Wisata, Cinta Alam are some of the places. Pak Mus and Sadar being my first choices there.
And Daniel if you have the time, the bus trip up to Banda Aceh stopping in Takengon for a day or two at the Gayoland Hotel (50,000/night) and then going through to Banda Aceh is definitely worth doing.
Just make sure you either book a seat on the bus ( in Kutacane) to Takengon or be out the front of your accomodation in Ketembe really early like 7 am to get an unbooked seat.
If you have the money you can stay at the big hotel on Lake Tawar ,but it costs 250,000/ night as I found out.
But the staff were wonderful there, made a phone call and took me down to the Gayoland Hotel by motor bike about 3kms away.
Very safe there. As a lone female travelling by myself I even ate in the street at midnight in Takengon and felt completely safe surrounded by only Indonesian men who were very courteous.
And a young guy came along who could speak a little english so I engaged him as my guide the next day to walk around the lake.
He is usually found in one of the streets as a parking man.
If you take a copy of his photo with you from my photos you will be able to find him easily. Sorry I have forgotten his name.
No permits are needed for Aceh now and travelling through is easy and an absolute delight.
In Takengon, there is a place near the Gayoland Hotel where you can book your bus to Banda Aceh.
Take the 10 am bus as you will usually be able to book the seat you want. 9am bus is always fully booked.
In Banda Aceh great place to stay is Uncle's Homestay.
Check other posts in the Sumatra forum where I have posted a load of information in the past.
Pulau Weh is also a great place to visit as well.
Check out my photos of Takengon, Banda Aceh and Pulau Weh in my signature area.
Have an awesome time as I am sure you will. So wish I was heading back there again right now.
P.S. You can get buses to Tangkahan from Medan, but the trip is a really long one over 5 hrs and on a road I am told that is worse than the Bukit Lawang road. Plus the last bus to Tangkahan from Medan leaves about 2pm.