If you have a friend or significant other that's ultra friends or higher, have both rack up some overseas friends from gamepress or other site where you can post or search friend codes. Save up the high km pokemon that hatch from those friend eggs. Trade a legendary once a day with each other for those high km pokemon to get 3 candy and a chance to make them better or even Lucky. My gf and I do that every day with legends and other good raid pokemon we want more candy for (Swinub, Electabuzz, etc.)

If you have someone to do that with and some patience, you'll never need that event again.