Do it this way to get best of your trip & less hassle
Day:1
Old city side
Landing and reaching hotel at Shahrah e Faisal: 1 PM by taxi
hotel to Quaid -e- Azam Mizar (as its on the way to Zainab Market from Shahrah-e-Faisal
Zainab Market, Atrium Mall
From Atrium go to Quaid-e-Azam House (the one near metropole hotel)
And by Magrib reach Port Grand but tell the driver to take you via I.I.Chundrighar road so you can have a look at famous Habib Bank building, KPT House etc
Day 2
Start day with PAF Museum & Maritime Museum,
Then head towards Dolmen City, on the way stop at Sea View (safer is to go to McDonald Sea View & view the water from there)
From Dolmen City go to Ocean Mall & have dinner at Zameer Ansari there on 4th Floor in open air (its better than Do darya)
Day: 3
hotel to Boat basin: 7-9 Am for break fast
boat basin then back to sea view if you want to see more water
beach to hotel/airport 2-3 pm by taxi
You won't be able to visit Tariq Road & Do Darya but trust me you wont miss on a lot; Do Darya is just food next to water which I after reading others feel isn't safe anymore (last I went there was over a year ago & it was pretty safe then) & since you're going to Zainab, Atrium & Dolmen City your shopping should be covered.