There aren't really enough walkthroughs to go about for ToGf especially when it comes to sidequests. I guess no one has a complete list yet but I hope my little contribution will help. I'll post what I can but it's only bits and pieces.
Finish Lineage and Legacies before doing any of this because then you'll have access to the Zhonecage.
Things you need beforehand:a) Flying Shuttle
-You should already have it.
b) Zhonecage (a bonus dungeon after beating Lambda in the main game OR completing Lineage & Legacies)
Thanks to the person who uploaded this.-Load your game (after beating Lamda OR completing Lineage & Legacies)
-Once loaded, there should be a skit saying "Errand Boys" so watch that.
-Go to Lhant and to the manor. There should be a star in the middle of the yard.
-After the cutscene with Frederic, the Zhonecage should then be added to Dungeons on your map. Go there.
-Find and beat Frederic.
-After that, you should have access to most of the Zhonecage's floors. If you already took the flute quest from Turtlez HQ then go ahead and beat Dark Turtlez on the Fourth Floor.
c) Argo Iris
-If you don't have it, then go to Ghardia Shaft and defeat the six golems where you use the Arithmos Cores on. A couple of them should be on the floor before Ghardia Shaft: Depths. I think you get it from an Abysseon.
d) Turtlez HQ Location
-X : 334.633, Y : 180.499
-Use Scan (L1) on that location
So then let me cut to the chase. I combined the steps for the two quests so you won't make any mistakes.
A handy flute that lets you call a Turtlez from anywhere, anytime. Now you can dualize whenever!
Excalibur-To acquire the Flute quest, go to the Turtlez HQ.
The holy sword once owned by Aston, now fully repaired. It's also known as the Eleth Sword.
P.ATK 151 C.ATK 302 ACC 76 CC 9-17
Saint  Enemy Weak to Nova = Damage +32%
-Talk to the Turtlez Boss at the north tent. He's going to ask you to find the Dark Turtlez.
-Go to the Zhonecage. Access Floor 4 and defeat Dark Turtlez.
-To acquire Aston's sword quest, go to Barona and into the Knight Academy. Once inside go left, back to where you found the password treasure chest. If you still didn't get the password it's "treasure."
-Talk to Victoria, she should be inside with a smiley face icon indicating the quest.
-Go back to the Turtlez HQ.
-Once there, there should be two people with smiley face quest icons. Talk to the one on the middle first, NOT the one on the right.
-After the cutscene, he'll give you the Turtlez Flute. To use it, just select it from your inventory.
-Then talk to the other one on the right.
-After the cutscene, he's going to give you the sword for free. You will now need to find a way to fix it.
-Go back to Barona and into the throne room where Duke Dallen is. Talk to him.
-Go to the Amarcian Enclave and talk to the Overseer.
-She's going to fix it for you if you have the Argo Iris. You should already have it if you defeated the six golems back in Ghardia Shaft.
-And now you receive the Excalibur.
So yeah that's how it went. :] Questions? Just ask and I'll try to answer.