When you download Kontakt Player (free), you get the Factory Selection. It includes an "Acoustic Guitar" patch with basic up/down strums mapped to different keys. It is not as robust as SGA2, but it is instant and free.
Once you've got your hands on Session Guitarist Strummed Acoustic 2, here are a few tips to help you get the most out of this amazing software: session guitarist strummed acoustic 2 free download