With colleges cancelling classes and the US government banning gatherings above ten individuals, you should set yourself up to teach your classes online.
If you publish a book, people will regard you as an expert. That will increase your marketability. It is also a good take-away for people who come to your talks and want to share your ideas. If you think you don’t have anything worthy of a book, you’re wrong. Everyone is an expert in something, is passionate about something. Writing a book will cement your own ideas, and benefit others