I'm so sorry I've neglected this forum and haven't come back to answer @philipnewton's question!
The Pennseythun Gernewek (Cornish Language Weekend) was WONDERFUL! There were probably more than 100 people in attendance, of all ages, too, which was a delight to see — families with small children, young adults, working people, retirees, the whole spectrum. Several different nationalities involved, too, including a few Breton and German visitors! Kernewek attracts a much wider range of people than I'd expected, which is very heartening.
There were classes during the weekend for all the different levels (along with a playgroup for the little kids) — complete beginners, first grade (my level), lower (second grade), middle (third grade), advanced (fourth grade), and fluent speakers , so everyone fitted in. Plenty of time to socialise, too. The hotel was a bit run down but they offered a decent price for the weekend, and the food was very good.
As well as the classes, we had a walk on the Saturday to visit a historic set of cottages that are now a museum, and entertainment during both evenings. On Friday we had a concert with songs from a Cornish language choir (Keur heb Hanow) and a singer/songwriter duo (Tir ha Taves). Saturday evening we learned some traditional Cornish dances with a live band and caller, followed by a sing-along session for everyone led by Revd Jane Kneebone, singing folksongs in Kernewek. Jane also held a short Sunday morning prayer service in Kernewek for anyone who wanted to attend.
One very interesting session we had was a talk from Stephen Gadd, co-author of this new book about Robert Victor Walling, one of the early Cornish language revivalists who hand-wrote his own magazine entirely in Cornish while in hospital during WWI. (All talks/speeches during the Pennseythun were given in Cornish with English translation, so we novices could hear the language spoken while not missing out on any of the information! ) There was a very active bookstall throughout the weekend with a big range of Cornish language publications, textbooks and other items.
We finished the weekend with a rousing rendition of Bro Goth Agan Tasow ("Old Land of Our Fathers", the unofficial Cornish national anthem) and of course a shout of "Kernow Bys Vykken!" ("Cornwall Forever!")
For anyone who's interested in attending next year (it's held in early April each year as far as I know), I would highly, highly recommend it. It was full of fun and friendliness and I met lots of new people — when you study a language that isn't commonly known, it's a real buzz to be with and get to know others who share the same interest. There's a real sense of community among Kernewek speakers, probably because there aren't that many of us, so it's good to stick together.