I got 100% on ele, but theres so many areas ive explored after 100%, i get the impression its a total of 105% if you count in bugged parts of the map and old arenas.
all in all, once you commit to it, and use the maps on this forum, it isn't too hard. Just do a couple zones a day, and in no time you will have it. I never used a running skill, just fought my way through it.
My Mesmer isn't a runner. I'm at 100% in Cantha and just under 95% in Tyria from fighting my way through everything. I'm hoping to have 100% in Tyria before NF comes out, though if I don't those heroes could make fighting through some areas easier compared to just henchies.