I was able to attend the Kofun lecture, and it was interesting, although since Kofun aren't really my thing I don't know how much I was actually able to follow. Theories were thrown around about how Himiko might be buried at Hashihaka, and how she may have been a shaman-priestess, rather than a "queen".
The Samurai Archives Forum now has monthly study groups that focus on reading and research on a specific topic. This month the topic is "Kofun", and is being facilitated by user "Nagaeyari". The next few are being worked out, but it appears that January will be the "47 Ronin", facilitated by user "Wave Tossed", and February will probably be on the "Shinsengumi", facilitated by myself. Basically what each study group entails is a "suggested reading list", as well as some materials provided if available, and a facilitator who "directs" discussion.
If you are interested in joining a future study group, drop by the forum and sign up.