I think it’s something around a 40k rep grind, give or take a bit. If just doing the Big Dig once a week (3k rep + a couple hundred from tomes) and the world quests (which should be six through the course of a week at 300 rep), I think you end up with about 5k rep per week, so it’d be about 8 weeks. (Additional Big Digs speed that up, though additional Big Digs are actually pretty unrewarding, resulting in just 300-400 rep).
I’m not sure how that measures up to the currency grind for someone wanting to get everything off the vendor. The currency grind at first glance looks like it naturally would go longer, but I may be misjudging that. (That’s kind of why I was hoping they’d have some capstone quest per rep level giving maybe an extra boost on the currency grind, like the Soridormi rep with the Time Rifts).