HOw old is your son? Does he struggle in any area other than writing? Many times kids with AS struggle with social pragmatics, attention/self regulation, organization and fine motor skills. Sometimes they have difficulty with listening/reading comprehension and math.

The IEP should contain goals for every area of difficulty. This often goes beyond writing and includes an organizational/classroom support goal, self regulation, Social and other academic goals. Your child's needs should drive the goal areas and there should be some data in the form of testing, teaching observation, work samples etc that you can use as a basis to determine his current level of performance and help to set goals for the coming year.

The 3 things you want to add seem reasonable and would go under the accommodations section of the IEP. On number 3 you mention an egg timer - another option would be to teach him to flip a "motor card" that would be on his desk to notify the teacher he needs a break. Part of a Self regulation goal might be to teach him to recognize on his own when he needs a break, to ask for a break (this is self advocacy) and then to take the break and engage in a strategy that helps regulate himself (maybe a short walk to the water fountain for example).

There are many other accommodations that I have seen:
1. Scribe as needed
2. Modified homework
3. Extra time
4. preferential seating
5. alphabet strip/ number chart on desk
6 . Head phones to block out noise
Here's a brief artical on IEP goals http://www.greatschools.org/special...ucation-program-iep-goals.gs?content=709
Here is an article on accommodiations: http://www.ldonline.org/article/Accommodations_for_Students_with_LD

The IEP should also include your concerns - the concerns can be about progress, how services are delivered, your child's emotional state etc. IDEA mandates this as part of the IEP to provide an opportunity for the parents to communicate what is on their mind. The TEAM should consider the concerns when developing the IEP to help answer them as much as possible.