You might look at a hotel for one of the nights. Either Surfside/Dockside or a nearby off-site hotel, to save 2hrs drive & 2 days of parking garage costs. Bring an overnight bag.
3 day tickets have a use period of 5 days or so, make sure to pick the cheapest date that covers all the days you want to go. You don't have to have tickets that start on your first day, they just have to cover every day you want to go. (IE if your first day is a Sat you might find that buying tickets starting Thurs or Fri is cheaper).
Download the Universal App, for ride wait times, schedules, map, hours, etc. Has a lot of useful info.
The last few hours that the parks are open will be your shortest lines. If you aren't doing open to close (which is a long day with an hr+ drive on both ends), you will do better to hit the evening hours than the morning ones. Especially
Epic! Make sure you can hang until the very end when nearly all the lines will be very short.
If you are going on a weekend day, try to put Epic on that day. The other parks are most crowded on weekends (esp Sat) and generally Epic is less crowded on weekends.
Bring collapsible water bottle(s) which you can fill for free with cold filtered water at the many Coke freestyle machines throughout the park. Or you could get one freestyle mug & share, take turns picking what drink to fill it with. Includes icees too.
Try to hit Hagrids around late lunch time or hop in line right at the end of the day. Do not go first thing in the morning without early entry, that will be the longest the line gets.
Note the water rides Popeyes Barges & Dudley Dooright flume
will leave you
soaked. The lockers for those are not free, you can bring bags on. There is a compartment on the barges which normally stays pretty dry (may want to put stuff in a big plastic bag in case), but expect anything on the flume to become soaked unless it is wrapped up. Feet/shoes too. These are waterproof sandal rides. You can also use the free lockers at Hulk or Forbidden Journey, you get the ride wait time plus 15min grace period - if the wait for one of those is nice and long, you are all set but don't go over the time or you will have to pay.