I have never been there, but I must admit my first reaction is that I would drive, not take the train there. The reason is that life in rural Norway is car-based, and you'll find it hard or expensive to get around without a car, even in a town like Hønefoss. Furthermore, chances are that your ancestors came from a farm near Hønefoss that can't be reached without a car.
As GUWonder says, you shouldn't have too much trouble finding your relatives, and genealogy is very popular here.
There seems to be a couple of hotels there, the Comfort Inn and the Grand Hotel.