Traveling to DebConf13 by train
The closest railway station to Le Camp is Yverdon-les-Bains. This page gives hints how to reach this from different countries by train.
 Traveling from Germany
From any railway station in Germany to Yverdon-les-Bains you can use so called Europa-Spezial Schweiz ticket + Bahncard 25. It costs 44.20€ per direction and is what you get (if you are lucky) on a research at bahn.de. Compared to the Europa-Spezial Schweiz Ticket without Bahncard 25 which is 59.00€ it is worth the Probebahncard 25 for 25.00€ if you do the full return trip.
The whole return trip is: 113.40€.
The tickets for a bicycle is additional 10.00€ per direction. You need to buy reservation card for the bicycle very fast to be sure that space is available. (It actually happened that the author of this text needed to change its return connection to get the bicyle back to Germany.)
 Traveling from France
There is a regional pass for Lake Geneva - Alps (130 CHF, 7 days), which might help getting from the french border to Yverdon.