Hello, Alicia! Thanks for bringing your question to the Disney Parks Moms Panel!
My daughter’s first visit to the Disneyland Resort was when she was just about 2 and half years old and it also happened to be during
Halloween Time. She had a delightful time and wasn’t spooked by any of the decorations around the parks. There’s definitely more to see and do now that Disney California Adventure Park has more seasonal offerings, but nearly every bit of Halloween fun at both parks is family friendly. This includes our friends from Radiator Springs dressed up in their Halloween costumes. The only costume that might be a tad questionable is Mater’s vampire costume because it features fangs. But it’s pretty tame and definitely not gory or ghoulish. The other costumes are Lightning McQueen as a super hero, Red as a clown, DJ as a punk rocker, and Cruz as a pirate (if she returns this year).
Most of the other décor around the parks is focused on fall foliage, pumpkins and jack-o’-lanterns, autumn-inspired bunting, and other seasonal tidbits. If your son is a bit timid, I would shy away from the statue of the headless horseman in front of Carthay Circle Restaurant in Disney California Adventure Park and possibly avoid
Haunted Mansion Holiday. Take a look at the video on Halloween Time attached to this answer to see if any of the décor might be a bit too scary. I can assure you though that during the daytime the parks are peaceful and fun and your little one will have a great time!
If you have any other questions, please don’t hesitate to stop by again. See ya real soon!
-Linda