In 2 days, you will be able to hit the 2 parks (the water park Volcano Bay is optional). Simpsons area - called Springfield USA - is in Universal Studios. Marvel Superhero Island is in Islands of Adventure. You can do one park per day or get park-to-park tickets to wander between the parks at will.
If you are planning to stay onsite (which is very convenient), you can choose between the premier hotels Hard Rock Hotel, Royal Pacific Resort, or Portofino Bay Hotel - these three will grant you express passes for all the rides except the new Hagrids coaster, and presumably the soon-to-be-open Jurassic Velocicoaster, on both check in and check out days - which is also rather convenient especially for a 2 day trip. Otherwise, those and other onsite hotels also come with early admission to one or both parks (likely both in July) and consistent reliable transportation to the parks.
Download the Universal App for an overview of the rides, park maps, menus, etc. It will also be your pathway to the virtual queues which are in use for certain rides during high capacity days. You can pop out easily to eat at any of the restaurants at CityWalk for lunch or dinner, or there are obviously options within the park as well. Don't discount the CityWalk options though, they really are super easy to get to and there are some really tasty places to try.
The level of detail in each of the sections is just mind-boggling, enjoy your planning and your trip!