Use FTP to download the site in full then run it via localhost on your laptop. Of course, you will need to install PHP and MySQL to get the message board part working.
Do a backup of the database on your site, then restore it on the laptop.
You will also need to edit the board's config file to let it know about its new home.
Fully script your demo. Nothing looses me faster when a vendor comes in to demo something and they have to hunt and peck at what they are showing.
I expect that they know their product inside and out. It does not give me the warm and fuzzies when they botch it up.
Don't assume that you will remember what you planed on showing. It don't work that way. I've been on both sides of this issue.
Hope it goes well for you.