Don't wait until a week before the race to figure this stuff out. Plan your race season out and send in your entries early. Call ahead for your lodging early. Most people keep a small journal or a few notes on races, the town, where they stayed, whether the liked it, and so on. It makes it easier the following season if you don't have to sit down and try and remember everything without notes, or call information for phone numbers.
Most organizations have some sort of mushers meeting.
Sometimes it is the first day of the race, sometimes it is the night before the first day of the race. The entry form should provide this information. If it does not, call the race giving organization to be sure. Whenever it is, be sure to attend. At this meeting, starting orders will be given, and mushers will be able to pick up their bibs.