Chile will be fine that time of year in a 4/3 booties and a hood.
I wouldn't take the train, that's not going to work. Just rent a car and drive it. But if you're looking for good waves that are less crowded I would suggest Baja or Mainland Mexico. It could be pretty flat for weeks on end unless there is a south swell or some random wind swell in the summer in SoCal. Mainland Mex is a cheap ticket and will be shoulder-head+ everyday in 80 degree water. SoCal will be 65-72 and may require a wetsuit depending on how long you want to surf.