Kerem's place is just amazing! It is even bigger than it looks on pictures- very spacious and with very high ceilings. The feeling of just lounging in the apartment is great. It was furnished with a lot of taste and was very cosy! I like that there was a sound system that you could put music on. The location of the apartment is also hard to beat. It is located off Istiklal, on a very lively street full of cafes and bars. We loved that when you go out in the evening you go straight into a lively street, but bear in mind that the apartment gets loud on Friday and Saturday night. The area around is amazing- just next to Cihangir and a lot of trendy restaurants and cafes in the streets around. We already have a dew favourites that visited couple of times and sure will visit again on the next visit.
As for transport links, if you want to go to Sultanahmet your best bet is catching the T1 from Tophane - the station is 10 mins walking, so quite convenient. On the way back though it can get quite tiring. All in all Kerem's place was perfect for us and we couldn't have asked for more. Will definitely come back soon!