Karachi to Hyderabad M-9 (1.5 hours)
Hyderabad to Moro N-5 (2:45 to 3 hours) 1st stop Royal Taj Restaurant for tea/refreshments/washroom
Moro to Sukkur N-5 (2:15 - 2:30 hours) I hope that M-5 would be fully operational by then so your 1st change over would be here.
Sukkur to Multan M-5 I haven't got an exact idea about how much time would it take but my guess is 4 hours +- 15 minutes
OR you can exit at Sadiqabad interchange and stay the night there at Midway Hotel, which is right at the highway (N-5) bang opposite a McDonalds. It's a 3* hotel but a very good one from the standards that you would find at the highway.
Now if you stay at Sadiqabad, you have 2 options, either to catch up Multan-Lahore motorway M-4 from Multan OR take M-3 from Abdul Hakeem.
If you choose option 1 (M-4):
Sadiqabad to Multan N-5 via Lodhran
If you choose option 2 (M-3):
Sadiqabad to Khanewal via E-5, which is the right turn just before entering Lodhran, cross Khanewal, drive up till Kacha Khoo take the left turn towards Abdul Hakim
I wouldn't be staying overnight at Sukkur, if I don't have anything else to do but to stay there. Either stay at Sadiqabad or better still Bahawalpur if you can manage the drive time.
Regarding your query about going from Sukkur to Lahore via Multan/Sahiwal, then I would advise you to skip Multan altogether and follow N-5 from Sukkur all the way till Lodhran and switch to E-5 from there and catch up N-5 again from Khanewal.