I know you said you were doing roasted potatoes, but, if you didnt' you could do a cilantro rice - I feel sure there are tons of recipes out there to Google.
I just made a jicama, granny smith apple, radish, and red pepper slaw. There are recipes out there for that too...just google jicama slaw.
Roasted veggies are a good side this time of year.
What time should we all be over?
Forget to say that fennel is a wonderful option. I love fennel and apple together.