If you've never been to Israel than after or before your conference spend time based in Jerusalem. I'd skip Haifa all together and since your not driving there is really very little point to trying to explore the North and figuring out public buses, your trip is simply too short for that (again, given your not driving). From Jerusalem you can get buses to the Dead Sea/Masada and all around the area if hiking is your thing (you mention trail running). Jerusalem is just a must.