Thika Road Mall (TRM) is located at Roysambu; few meters from the highway.
From Bus Station, BS
If you are on the BS side, go to Ronald Ngala St. and board Githurai 45 buses available along the street. Common buses include Nicco Movers, Virginia Coach, ZamZam, and others. You can board any bus heading to Githurai 45. Tell the conductor to drop you at Roysambu. Once in Roysambu, TRM will be visible to you.
Alternative: From CBD, commercial
If inside CBD, board Githurai 45, Githurai 44, or Kahawa West buses available along Tom Mboya St opposite the fire station. The recommended matatus include Zuri, Marimba Investment, or Unified Poa. Tell the conductor to drop you at Roysambu. Once in Roysambu, TRM will be visible to you.