For the normal levels 70-79 quests, please visit this page:
70-79
NOTE: This information is incomplete. Anything with **** is a gap that I have not yet filled in and there may be more information that I am not yet aware of. This is based on my personal experience coming from multiple (about 13-14) runs into the Frostcovered Lands instance in SOLO mode. I cannot completely confirm all of the information for the SQUAD mode as I have yet to complete it in full. Thank you :)

Level 75 Quest: Disappeared City

1. Speak to Taoist Yu (153, 964) Snowy Village
Opening the Gate Mode unlocked
Single Mode unlocked
2. Continue on to Level 75 Quest: "Comforting Jade"

Level 75 Quest: Comforting Jade
-Continued on from Level 75 Quest "Disappeared City"
1. Speak to Taoist Yu (153, 964) Snowy Village
-Obtain 1 Curvant of Jin
-Obtain 1 Curvant of Yi
-Obtain 1 Curvant of Li
-Obtain 1 Curvant of Chih
-Obtain 1 Curvant of Hsin
-Obtain 1 Curvant of Ming
-Obtain 1 Curvant of Tao


Takes 7 Fragments of each type plus one essence to make a Curvant.

2. Report to Taoist Yu (153, 964) Snowy Village
Squad Mode unlocked

Level 75 Quest: Wounds of the Frost
1. Speak to the Elder of the Streams (130, 858) City of a Thousand Streams
2. Speak to the Frost Adventurer (152, 965) Snowy Village
-Collect 1 Mysterious Pendant (Farm from Lin's Remains located at [116, 962])
3. Report to the Frost Adventurer (152, 965) Snowy Village
4. Speak to the Frost Resident (151, 891) North Barrier Village
5. Speak to the Orphanage Owner (159, 894) North Barrier Village
6. Speak to the Frostcover Necromancer (154, 895) North Barrier Village
-3 Paper Crane
7. Continue on to quests "The Genesis- Paper Crane", "Save the Souls", "Revived Murderers"

The following quests must be completed in Squad Mode of the Forgotten Frostlands. In order to access Squad mode, the quest "Disappeared City" must have been completed. The leader of the party must have completed squad mode in order to participate. There must be AT LEAST 4 members in the party. The mode will not open if members of the party do not have squad mode unlocked, but this can be bypassed by having the members outside of the instance while the leader opens the instance within. There has been a reported bug that the quest mobs do not register in squad mode but from what I can tell, it appears that the mobs do not register only if you do not have squad mode unlocked (aka, you MUST complete the quest "Comforting Jade"

The Genesis- Paper Crane
-Continued on from quest "Wounds of the Frost"
1. Speak to the Frost Recluse (391, 999) Thousand Wood Ridge
2. Speak to the Elder (433, 887) Etherblade
3. Speak to the Elder (327, 427) City of the Plume
4. Speak to the Untamed Veteran (245, 648) City of the Lost
5. Speak to the Frost Recluse (391, 999) Thousand Wood Ridge
6. Continue on to Level 75 Quest "Frostcovered City"

Frostcovered City
-Continued on from quest "The Genesis- Paper Crane"
1. Speak to the Mountain Priest (Located within the second to the last room of the Forgotten Frostlands (The upper-right corner room) in squad mode)
2. Kill 1 **** (Located within the Forgotten Frostlands)
- ***
-Reward (Coin: 100000 Exp: 200000 SP: 40000)

Lost Souls
-Continued on from quest "Wounds of the Frost"

1. Speak to the Frost Adventurer (152, 965) Snowy Village
-Obtain 9 Adventurer's Soul (Quest drop from Glacix: Elemento in Squad Mode of the Forgotten Frostlands)
2. Report to the Frost Adventurer (152, 965) Snowy Village
-Reward (Coin: 70000 Exp: 90000 SP: 18000 Rep: 8)

Revived Murderers
-Continued on from quest "Wounds of the Frost"
1. Speak to the Frost Adventurer (152, 965) Snowy Village
-Kill 1 Galacix: Elemento Lord (Located in Squad Mode of the Forgotten Frostlands)
-Kill 1 Galacix: Arch Aeolian Shadow (Located in Squad Mode of the Forgotten Frostlands)
2. Report to the Frost Adventurer (152, 965) Snowy Village
-Reward (Coin: 80000 Exp: 100000 SP: 20000)

Ruthless Ones
1. Speak to the Frost Recluse (391, 999) Thousand Wood Ridge
-Kill 5 Glacix: Jaeger (Located in Squad Mode of the Forgotten Frostlands)
-Kill 5 Glacix: Aeolian Shadow (Located in Squad Mode of the Forgotten Frostlands)
-Kill 5 Glacix: Wu (Located in Squad Mode of the Forgotten Frostlands)
2. Report to the Frost Recluse (391, 999) Thousand Wood Ridge
-Reward (Coin: 70000 Exp: 90000 SP: 18000)