I wouldn't hold chicken for 3 hours. Raw chicken will cook in half that time, so I imagine it'd be really dried out by then. Grandy's and KFC can pull it off, but I don't know how.
For a much shorter while, I'd use a low oven and a loose cover (or no cover) so that your crispy crust didn't get steamed. Is there a point to which you can make the chicken ahead, & then do just a little work at the last minute? Ina Garten does fried chicken that way for exactly that purpose, so I'd check foodnetwork.com for her method & do that. She's all about not cooking at the last minute when you're having a party.
She keeps taters warm in a double boiler; check the site for that, too. I imagine a little extra liquid couldn't hurt. Tightly covered in a low oven might be better than a crockpot, unless you're stirring it once in awhile in the crockpot--would hate to have the edges burn.
Sounds great--what time should we be there?
ETA: misskitty100, great minds think alike, as we were posting at the same time! :-)
If you're afraid of butter, use cream. ~~ Julia Child
As you cook, you enjoy omniscience about food that no amount of label reading can match. Having retaken control of the meal from the food scientists, you know exactly what is in it. (Unless you start w/cream of mushroom soup, in which case all bets are off.) To reclaim control over one's food, to take it back from industry & science, is no small thing; indeed, in our time, cooking from scratch qualifies as subversive. ~~ Michael Pollan