4 days trip to Punjab is like going to touch and come back. Your best bets are places which you can reach within 8-10 hours of travelling. There are a few beside Gwadar, for example Gorakh Hill, and Tharparkar. Gorakh will be cold being a hill station, and Tharparkar will be very pleasant these days.
You can visit Mithi, Nagarparkar, and Islamkot in these 3-4 days AND can also combine Umerkot with it.