[item=130072] can be found inside the Ocanus Cove cane, not above it in on hill. There are a path down to Arena in front of Celea, at the other side of lake, get there and then follow to 48.2 50.5 point, there's an entrance to Oceanus Cove.
TomTom:
/way Azsuna 48.2 50.5 Oceanus Cove entrance
After the quest you'll get these recipes as a reward:
Reclaimed Cargo, www.youtube.com/watch?v=SOnBc4wg8y0
There are many leatherworking profession quests in Legion, 42 total, check out under the spolier, if missed something. You also need to be at least 600 in Leatherworking to pick up the final quest Mounting Made Easy, which rewards you [item=141850] recipe to "craft" Great Northern Elderhorn mount.
Spoiler
Both leather and mail quests:
1
[spell=201705]
https://www.youtube.com/watch?v=VZEl3FfeFhM
2
[spell=194898]
http://www.youtube.com/watch?v=sQ-Dr9X8mGk
3
http://www.youtube.com/watch?v=SXcSpIQs0oM
4
http://www.youtube.com/watch?v=A3uY7JZugSU
5
[spell=196574]
http://www.youtube.com/watch?v=kgtxlzZslyI
6
http://www.youtube.com/watch?v=X2lyCk0lwW0
7
[spell=196443]
http://www.youtube.com/watch?v=OQnBb-IirPw
14
[spell=194813]
http://www.youtube.com/watch?v=0thJLADNjyQ
38
http://www.youtube.com/watch?v=sUVUqAf6sd0
39
http://www.youtube.com/watch?v=EEkuIZCAIIk
40
http://www.youtube.com/watch?v=RctgdyNjwC4
41
[spell=195326]
http://www.youtube.com/watch?v=2l0DfQ2V0QQ
42
[item=141850]
https://www.youtube.com/watch?v=Q0bZyew_YSE
.
Leather armor quests:
8
http://www.youtube.com/watch?v=_WMKLnphwxw
9
[spell=194862]
http://www.youtube.com/watch?v=eJyRwf-Cxsg
10
[spell=194830]
http://www.youtube.com/watch?v=R5-iVrUHetU
15
http://www.youtube.com/watch?v=giovYVFtfyc
16
[spell=194952]
http://www.youtube.com/watch?v=uN2gX-G4LIY
17
[spell=194948]
http://www.youtube.com/watch?v=JYNN4MPcak0
18
[spell=194997]
http://www.youtube.com/watch?v=X0k2iW28SIs
19
[spell=194976]
http://www.youtube.com/watch?v=ZfovjcxTieU
32
[spell=195098]
http://www.youtube.com/watch?v=Ep18dVM98tQ
33
http://www.youtube.com/watch?v=5_rQ673lNjA
34
[spell=216233]
http://www.youtube.com/watch?v=7atTI4WGP4A
35
[spell=216231]
http://www.youtube.com/watch?v=lkRgpLCdbUs
36
[spell=216232]
http://www.youtube.com/watch?v=3ESnQhl2sW4
37
http://www.youtube.com/watch?v=wlCPu5nMkic
.
Mail armor quests:
11
http://www.youtube.com/watch?v=sU7P8ocXGxU
12
[spell=194891]
http://www.youtube.com/watch?v=yzDTzHuB5bQ
13
[spell=194892]
http://www.youtube.com/watch?v=aG8APjjvD20
20
http://www.youtube.com/watch?v=T5o7jBOYJto
21
[spell=194965]
http://www.youtube.com/watch?v=gCucU_F5kY0
22
http://www.youtube.com/watch?v=FdX8Mc3PmM0
23
[spell=196065]
http://www.youtube.com/watch?v=DWXs_VPl5LE
24
[spell=195003]
http://www.youtube.com/watch?v=SOnBc4wg8y0
25
[spell=194959]
http://www.youtube.com/watch?v=uweBrxlbrbk
26
[spell=195101]
http://www.youtube.com/watch?v=1NXn6PvpXs8
27
http://www.youtube.com/watch?v=o9TPFQdMXds
28
[spell=216234]
http://www.youtube.com/watch?v=fDhVoS4zT84
29
[spell=216235]
http://www.youtube.com/watch?v=JnkP_iieQ9w
30
[spell=216236]
http://www.youtube.com/watch?v=W_amvI6OYVA
31
http://www.youtube.com/watch?v=mt4TA7ouSSs