How?
That's a good question. From my experience, it's more about a week each.
For Zerith, I did one Elsweyr Defense Forces and one ToT quest each day, played 3 to 5 matches of ToT daily, but getting to the last companion quest still took me 5 days, and another 2 days to get to max rapport (last companion quest triggers earlier). Just reached that today. So, one week in total.
Now I still have to level him to 20 (he's at 7 now, from running around in the Archive each evening) and find a beggar somehow (tried it today, travelled to over 30 locations where they may spawn, but no luck so far).
DenverRalphy wrote: »Zerith has numerous likes to captilallize on. IA and Dark Anchors especially, which also mixes in the killing of skele's/vamps/dro-m dro-ma'thra. Rotating in killing a dragon each hour. Drinking purifying bloody mara. Looting heavy sacks. If you mix them all together in a rotation for their cooldowns.. easy peasy.