am wondering if I can get by with a nice button down shirt and dockers (no tie or jacket).
Absolutely. Not a problem. I wish they'd drop the silly "smart casual" terminology. Few pay attention to it or differentiate it from regular casual. It's like lines which still use "semi-formal". What is that supposed to mean? I guess I could wear blue jeans, sport coat, t-shirt, and a bow tie and cummerbund and say "I'm semi-formal".