OK, I guess it'll be alright... I changed the filter last fall before putting the bike away for the winter... I've put 2400 km on the filter so far this season so by the end of the trip it'll have about 10,000 km or 6,000 miles on it.
I'll probably change the filter along with the oil when I get back home. Alas, there won't be much riding left in the season if last year is any indication (wet fall, early winter up here).
I just finished Day 1 of the trip today... 681 km. I think that's the longest 1-day ride of my life... I'm pretty stiff but otherwise it was no problem.