Is your tour similar to the following

DAY  1 :  MEDAN – TEBING TINGGI – PARAPAT / SAMOSIR (L,D)
Pick up at at Medan city hotel, then transfer to local restaurant for lunch. Continue the journey to Parapat, drive along the beautiful road which offers the endless view of rubber, palm oil,cocoa plantations and paddy fields. Stop at Pematang Siantar to buy some local snacks : ting ting, tengteng, kerupuk / crackers  etc. Arrive in Parapat, Check in to hotel and  dinner in Parapat.
Evening walk / shopping / nite life in parapat / samosir island.

DAY  2 : PARAPAT -  SAMOSIR ISLAND TOUR - BRASTAGI  (B,L,D)
After breakfast at hotel, Samosir island tour by boat : visit Tomok kampung to see the  Batak King‘s tombs / Raja Sidabutar and Ambarita  kampung to see the traditional Batak village with  the stone court and the execution place / Raja Sialagan. After lunch  in Parapat, proceed to Brastagi, a mountain resort with it’s refreshing weather and magnificent scenery which has an abundance of flowers, vegetables and fruits : visit  Simarjarunjung / the highest point by Lake Toba, the ancient King’s Palace of Batak Simalungun / Rumah Bolon and  ipiso-Piso waterfall. In Brastagi  visit Gundaling hill to see the  two active volcanoes in Brastagi : Mount  Sibayak (2.172 m) and Mount. Sinabung (2.417 m) and PasarBuah / Fruit Market. Check in to the hotel and  dinner in Brastagi. Evening  walk / shopping / nite life in brastagi.

DAY  3 : BRASTAGI – MEDAN (B)
Morning take ride to Medan, city tour and shopping in Medan : visit Istana Maimoon / Sultan Palace,  Mesjid Raya / Grand Mosque, Batik house, pusathandbroidery / sulam / telekung, etc and  Medan Mall / Sun Plaza. Transfer to Medan Hotel.