WMS recommendeds ibuprofen for altitude sickness. There is a small study that shows a benefit to aspirin, but it was using 320 mg tabs every 4 hours. WMS states there is insufficient evidence to recommend aspirin (same with Tylenol).
Over all, stay well hydrated, get good sleep (especially on the first few nights), avoid alcohol (again, especially on the first few days), and try to give time to acclimate (drive in rather than fly, stay at lower elevation the first night, Etc).
81mg (baby) aspirin daily is about as far as one can get from toxicity.
www.ncbi.nlm.nih.gov