Interior/Exterior switch halogen bulbs to LED's are a good place to start. If I were going to just keep the factory look, I would do the following 3 mods.
1. Replace Interior/Exterior bulbs with LED's
2. Replace headlights with LED bulbs
3. Replace the side view mirrors with the Rav4 Blind spot mirrors (direct retro fit replacement).
These should really already be incorporated from the factory into the 4Runner, especially in the higher trim level versions.
switched out all interior lights, license plate lights and back up lights as well.
What a difference.