You must mean the fairyland quest? It's a good tactic to leave an alt in ow with none of the quest complete. Then as soon as a boss or mini spawns you can see its up.Then no notifier when boss backIf you stay grouped with your alt you'll both get gold bonus then pass the gold from your alt to main.I use alts while i duel device so Ik when a boss is up. When I kill boss I simply ungroup alt.
Other than that if there is room you should always group alts. You get upto 3.1x more gold.
Personally my best gold making comes from carrow gold bosses. There are 14 bosses and if you log 8 toons you get 16k gold absolute minimum from lowest level spider to nearly 60k gold for the highest firbolg max. Average gold per kill is around 35k or so. The direct gold is handy no merching for hours and hours. I only have 5 mains so i usually just log the three low level alts i have parked at each carrow gold boss and group everyone.
Using this method i have farmed over 500k gold direct in a single 6hr period no merching.