Generally speaking, I can get any phone or address for a person. I say generally, because although I'd love it to be, not every number is online.
If I can't google it (or whitepage.com it), and it's not in my area of Michigan, I'll tell the person to call the library nearest the person/place they're trying to reach. They'll generally have a Polk city directory and be able to look it up much better than I can, since I only have 2 counties worth of Polk city directories.
A senator/representative is sometimes much harder to get a phone number from. Some of them seem to be only through e-mail, which for someone who doesn't have a computer or access to a computer is very limiting. So I do my best, and give them the best information I can.