Opening up an engine far enough to do a valve check is always a bit risky just before a planned ride. Lots of people do it and get by with it. But stop and think about if YOU want to be the one guy who doesn't get to ride because he's sitting around waiting on parts.
You should always have a valve cover gasket, coolant rail O-rings, fresh coolant, and a set of spark plugs available for every FJR valve check. There's no sense going that deep without changing plugs, and you never know when a valve cover gasket will stick and tear.
In ALL cases, I strongly recommend NOT doing a valve adjust unless the bike is safely positioned in a shop where it can live for several days if necessary. Valve check is one thing... Valve adjust is something altogether different.
Who knows, I may have time to attend this year's event. Hey Ed, can I ship you a box of tools???