I am a real sticker on preparing in advance. There are some rare instances when preparing too far in advance could cause you trouble. This is one of them.
Let's say you have access to your presentation room the night before, so you visit the room and decide to put your opening dry erase board comments on the board.
The next day you start your presentation, talk for 15 minutes, refer to your dry erase board comments for several minutes and then you go to erase them. --- oops. They might not come off without some serious scrubbing of the board.
This happened to me once and I had to hold the back of the board with one hand and scrub each little inch of writing really hard to get it erased enough to continue.