Alternative to Elite quests (how long to grind)

[Lorentary]

TL;DR version: How much grinding should be done if a group cannot be found for important elite quests?

For the Elite quests at higher level there should be an alternative guide (or basically just a Grind to X) as the low number of players in the 35-55 range makes it nearly impossible to find a group.
I'm here specifically referring to the Searing Gorge quest [The Flame's Casing] in which many elites have to be killed for a low chance of getting a quest item. This quest unlocks a quest-line but is impossible to solo (at least at level) on most, if not all, classes.

[ZG Support 1]

If you feel a quest is too hard you can skip it but just be aware that doing so may make other quests unavailable later in the guide. As for how much grinding, you really only need to grind if you hit a step that says to grind to the next level.