Our almost 3yod son has SPD. He is mostly a seeker but is defensive to sounds and anything touching his hands and feet. He will spend the day crashing into things only to turn around and accidentally touch something squishy and completely break down. The biggest help is to have a "safe" area that he can retreat to when the noise/lights/movement gets to much for him. For now it is a cozy corner behind a chair but dh is working on building him a tower in the corner of his bedroom that he can escape to.
I read a ton of books on the subject when we first found out, but found Raising a Sensory Smart Child
by Lindsey Biel and Nancy Peske to be the most helpful from a parenting point of view. They do a really good job at explaining why they do the things they do at therapy and how it helps them. Ds has been going to Occupational Therapy since October of last year and speech therapy since January of this year. There has not been much change in his behavior as of yet but it has helped to understand why he gets upset so much and how to help him. I recently tried to get a support group started at the therapist office but had not success, most people get their child's therapy at the public school and since we homeschool their just wasn't a big enough demographic. I really look forward to talking and sharing ideas with you ladies, I know I for one really need the help/advice, it's like learning to parent all over again.