Go to SF. Look, there's 6 other people in your current office. Assuming that your software project is ready, you have a 4 days (counting today) to bring someone else up to speed on it. Make an excuse, call in sick, or just tell the truth.
Also, don't forget about doing both. Is there some reason you can't VPN into your office from SF and give the demo virtually?
Also, don't forget about doing both. Is there some reason you can't VPN into your office from SF and give the demo virtually?