A hunting lodge built by Sultan AbdulMecid in the middle of the 19th century on the Asian shore of the Bosphorus close to the second bridge (Fatih Sultan Mehmet Bridge) and to the village of Anadolu Hisarı. It is Dolmabahce Palace in miniature. The guided tour is only in Turkish but there is often someone around who will translate for you. Open daily except Monday and Thursday, entrance is only 4TL. After your visit, turn left and walk the five mintues to see the ruined castle at Anadolu Hisari. There you can find several cafes on Kucuksu stream where you can have a meal and enjoy watching the fishermen and pleasure boaters pottering around.
www.allaboutturkey.com/ist_pal.htm#kucuksu
Take a ferry to Uskudar and then hop on a number 15 (to BEYKOZ) bus from in front of the mosque opposite the ferry terminal for the 30 minute (or so!) journey up the Asian shore of the Bosphorus, passing the summer palace of Baylerbeyi on the way.
Is this your business?