FAST potluck dish?

I made Merrill's farro salad last night for dinner and I prepped everything in the morning. You could cook the farro and mushrooms while you're getting ready for work in the morning, chop the parsley, and prep the cheese. Then just pack it up with a lemon and some olive oil and stir it all together at your host's house. Really easy. http://food52.com/recipes/5710_farro_salad_with_roasted_mushrooms_and_parmesan

Why assemble at the potluck? Make ahead and freeze - is that a possibility? Here are some favorites
http://food52.com/recipes/16467_roasted_celery_soup
http://food52.com/recipes/9113_farro_risotto# - this is amazing
Ripe pears, spread with goat cheese - amazing
I know I am overusing the word amazing ...
In your own kitchen saute fresh kale with garlic, onions, pancetta or bacon and a little serrano pepper.
Store in refrigerator or freeze. At your host's home, boil pasta and toss with your pre-made ingredients. Add a little goat cheese, good to go.
Another possibility is to just offer to bring wine and potato chips. No one says no to that!

I don't like bagged salad greens at all (pet peeve) with the exception of arugula, it is usually fresh. You could assemble an arugula salad with a decent bottled dressing (i like brianna's or p. newman's) and other easy items like olives or grape tomatoes, nuts, cubed cheese?
If chopping/prep is OK another salad would be a watermelon-feta type thing? melon and prosciutto?

A bag of baby Lima bean. Blanch them the night before---they should still have some bite to them, not mushy--always taste for doneness. Dress with lemon juice, olive oil, oregano, a touch of salt (very light salt) and pepper and a bit of garlic powder (or fresh in the dressing). Put that in the 'fridge overnight. At the party add some crumbled feta cheese and parsley before serving.

Caprese salad? The assembling on site part is a challenge, will reply if I think of anything else...