Warriors and Warlords takes place in a huge city park in Boscobel, Wisconsin. The supply of electricity is limited, so I can't use my favorite period medium - PowerPoint. Still, I scored a few points for Wikipedia in a class on evaluating sources for SCA research. The most important question to be asked is, how much research is necessary for the task? For some questions, one source is sufficient. For other quests, the world is not enough.
Also, what, really, is the task? If I were researching appliqué to teach a class, for example -- "How to Spiff up a Campsite" and "Fifteenth-Century Needlework Techniques" would have very different requirements.
I hope I made it clear that a variety of independent sources were useful to bring one as close to the object of one's research as possible.