Walaykum Assalam,
Brother these are my findings
Route-1: You will face bad jams upon exit from M2, and its wastage of time and fuel as you have best alternate Route available. (Experienced)
Route-2: Its good one but when alternate is available which is shorter, then why choose the longest way to approach OKARA spending extra Fuel and time also. (Experienced)
Route-3: The Best route till OKARA, Road Condition, you will cover InshaAllah very fast and easy approach to Okara. its shortest route and save Time and Fuel. Don't forget to eat NAAN TIKKI at Railway Phattak towards Exit from Okara to N5, its really Tasty :)(Experienced)
One more thing regarding this route, if you don't want to touch local road, as its traffic changes time to time, and also when we drive on road like motorway & then leave towards local road, its become hectic most of the time, therefore stick to Route 2, which is no doubt clean road, with less traffic, though it have greater KM's but still have same time to approach Okara.
Route-4: No need to touch when best one is already available.
Have a safe Journey and share your experience upon return brother.
JazakAllah.