Need help in California

Hi guys.
Next week my son turns four and as I promised him, we are going to Legoland in Carlsbad, CA. It is a tradition of sorts to go to the zoo on his birthday, so we are going to be in San Diego. So, does anyone know of a hobby shop or memorabilia store of sorts in the area that would have a good selection of diecast? I'll be staying in Carlsbad for a week and any help would be greatly appreciated.
Also on the way there we are spending a couple of days in Vegas, so any suggestions about shops in the sin sity are also welcome.
Thank you in advance.