After many days & visits to Winterspring, the [Reins of the Winterspring Frostsaber] is now mine!
The grind for the Wintersaber Trainers begins and ends with Rivern Frostwind in Winterspring.
A basic break down of the reputation is this:
Frostsaber Provisions (250 Rep) is the only quest until neutral 1500/3000.
Winterfall Intrusion (250 Rep) quest will be available once you’re halfway through neutral.
Rampaging Giants (350 Rep) opens up after Honored is achieved.
All three quests are available to repeat as soon as you unlock them through the different levels in reputation. I would recommend that you continue to do all quests as they open up. You might think that the Giants are too far out of your way to bother with but all you need is a kill for 4 of each, no looting required.
I abandoned this rep grind after reaching my [40 Exalted Reputations] (many months ago) because it was a really active area. It still is after all this time but only competing against 1-3 other players for the quest mobs is not too bad in my book. It was quite tolerable especially knowing that there is a feat of strength being added in Patch 3.2 that you receive for obtaining the Winterspring Frostsaber mount (seen below). The achievement was enough reason for me to revisit the grind and complete my 43rd Exalted reputation.