You can meet Paterson or hear her speak at one of these events listed on her website.
You can see a memorial for Lisa Hill (the real-life inspiration for the character of Leslie) at Takoma Park Elementary (which becomes Lark Creek in the book). (source)
Paterson doesn't know what happens to Jess after Bridge to Terabithia's conclusion. (source)
Paterson is the United States' National Ambassador for Young People's Literature for 2010–2011. (source)