Recommended Walk
Start at the waterfront at Eminönü
Should see docked boats serving fish sandwiches (balık ekmek) and purple pickle juice
Walk up the hill towards the Hagia Sophia (Aya Sofya). Can take the tram to save energy.
Visit the Hagia Sophia
Eat at Tarihi Sultanahmet Köftecisi
http://www.sultanahmetkoftesi.com
Traditional style meatballs (köfte)
Eat in and pick single or double portion, or do takeout sandwich if there is a line.
Other options
Blue Mosque
Can be quick
Basilica Cistern
Surprisingly cool, doesn’t need to take too long
Grand Bazaar
Noteworthy, but a bit repetitive to spend a long time