Where can I find Helium 3 in our solar system? What are the best locations within the solar system to find Helium 3 excluding the Sun? Where is Helium 3 most abundant after the Sun?
You wouldn't need to travel too far, the moon has been bombarded with large amounts of Helium3.  

https://www.esa.int/Enabling_Support/Preparing_for_the_Future/Space_for_Earth/Energy/Helium-3_mining_on_the_lunar_surface