I see this question so often in ToS, I have taken atleast a dozen characters past 280 in my time and I have never grinded before maven abby, I completely skip alemeth, evacuation zone etc.
Take advantage of your dailies, you need to do all 3 silaui missions every day. Make sure when available, you utilize the 600% exp boost of the instance finder for dungeons. When you get to a new pve map do the monster kill achievments for additional exp cards.
With all the exp buffs that IMC hands out now there is no reason whatsoever for people to hit that old 160 exp dead zone. My newest alt (4 days old) is already lv160 and I havent gotten past lv90 pve maps yet. That 160 is simply off daily fedi missions and dungeons using a crap ton of cookies and the occasional scroll.