Hi Thistles, first of all nice guide ^^
I have a level 17* gunner fox and I can give some advice for people who don't really enjoy doing those quests or that wanna fight Don only later. I trained from level 70-100 at swamp 6 and Techi1. Of course, techi1 and Swamp6 aren't as active as they were before and there are usually male parties at Techi1, but if you find one you can fit or you can slave friends to party you, you will get great exp killing kilimanjaros at Techi1(stay away from Lakis T.T) and Arachnes at Swamp6(stay away from Mud Bigfoots).
I avoided Path to Snow Hill because it was too crowded and Jokers didn't give me that good exp, and since it is a narrow field I was often mobbed.
From level 100 to 3rd job you can try training at SF3, since bears give good base exp(crappy tm exp thou, but you can get tm with quests, etc) and I could 2 hit them at that level, hit and run.
When I trained Wishey, Ghost Blue was still for level 20 people and Mirage Island didn't really exist, maybe they are better training points and ghost blue has some good quests, but anyway, I hope those advices help future gunner foxes.