So once we have the broad outline of the event is when the fun bits really get underway, fleshing out that outline into an event concept that holds together. Balancing what’s practical, what should be fun, what’s actually doable, what people will be willing to do.

So what we have so far is a bonfire on or near the Spring equinox. Now I could be really obvious and do something Celticy, we used to have an event in Spring called the Celtic games and that was a lot of fun so I could just revive that. But something made me look a bit further north for inspiration. It didn’t take much poking around to discover that Idunn, the Norse goddess of spring, was also the keeper of the golden apples of immortality, and had a bit of an adventure wherein she was kidnapped by a giant. On realising that they were getting old and doddery the gods sent Loki (of course) off to retrieve her and he turned her into a nut and carried her home in the form of a falcon, while being chased by the giant in the form of an eagle. He got her home safely, but what if he hadn’t? What if, say, he dropped her, and her precious apples into our back yard?
So, now we have an event featuring a bunch of golden apples, and a nut. A treasure hunt for the golden apples and other Norse activities. Ideas kept percolating, being assisted by occasional (and I use the term very loosely) ‘research’ and this is where I got to.
Event to start around 12 or just after lunch. To start with an archery competition, probably a wand shoot, but definitely an apple shoot (real apples required, equine quality* + personnel: range master). Next a market for all the ‘peaceful Norse traders’, this could start perhaps half an hour after the archery begins so that our events overlap. Overlapping events can work really well to avoid gaps in the schedule and provide alternative activities for people. Once the archery is over start setting up the space for a holmganga ‘tournament’ (holmgangs are more duels but it will do for a Norse tournament format). 
After the fighting some games to keep people active and warm. Back in the day when we used to have a Celtic games event one of those games was spiking apples* from ‘horseback’ so that would be a goodie. Another possible game is something we did at an event in Calafia, the game was called Knotlickr, I don’t remember exactly how it was played, a bit like field hockey? A quick hunt around the internet suggested that they hadn’t had that event for a while and no rules online so I’ve emailed the Calafian seneschal to see if they can help.
Then light the bonfire, before it’s really dark. Bonfire placement will be critical but I’ll consider layout later. Potluck dinner early, some bardic, assisted by prepared short poems and riddles for people who haven’t brought anything and then end, not too late.
While this is all going on I’m going to have an ongoing search for the hidden golden apples. Also have apples as prizes for the different events, and maybe some spares for spot prizes. Then at the end of the event see who has the most apples and they get a Norse gift basket, or prize. That gives people opportunity to do some canny trading to accumulate apples. It’s not as organised as an actual quest, and I’m not really a fan of quests at events, but it still provides something to bind all the activities of the day. People can ignore it if they like, or get really involved and go treasure hunting.
So, now I have the general plan for the event, a theme binding it all together, a date and site. My next job is to get approval from the local group which requires a budget. To do the budget I need to know what I’m going to need to buy, which means fleshing out the activity in detail. I’ve also decided that I’m going to need some help so recruitment is in order.
* horse apples will be required for some activities, these are cheaper than eating apples and will be willing consumed post event by said equines.