Not sure how to do it in 1-2 hours, but I've done it in less than 3 on a few toons.
Second post is the basic idea. Only time consuming part is 90-92...rest takes like an hour.
That seems really elaborate for the time took, I don't do any of that. I just pop an elixir and then start picking up treasures. Each of my characters take 4-5 elixirs and all of these are popped in succession except for one around level 94. At 94 I will take a little break and get all of the bonus objectives in Gorgrond near complete (except for the pale orc because I dislike it and the one in the far east part of the zone because it is out of the way) and then I head to Talador and get the shredder/lumber bonus objective near complete and the scared cat bonus objective near complete. Then I fly back up to Gorgrond, pop an elixir and finish up the bonus objectives (while picking up easy treasures along the way) then finish those 2 in Talador while picking up easy treasures. After that I fly down to Spires and pick up treasures until my current elixir fades then depending on how many treasures are left in the zone/my level I will either stay there and hit 100 or fly to Nagrand pop the next elixir and hit 100 there.
Nothing fancy to be honest, I don't pick up all the treasures either, just the ones that don't require going inside places you can't fly unless said place is really small and can be gotten in/out of really quick. Also in all of these cases I've gone with a full bar of rested xp (not intentional but you probably should) since treasures will consume rested xp. I've leveled 4 characters this way now and it's gotten slightly faster each time as I refine the process (basically which treasures are worth picking up). I guess on my next character I could legit time myself but I was mostly estimating the time based on 4-5 elixirs (which is 1 hour/1 hour 15 mins) and the time it takes to stop and do those bonus objectives I listed (speed here depends entirely on the class you're playing, how much you suck at it, and how good it is generally for speed killing). Oh also
incredibly important, you need Archaeology before you start because a ton of the Spires treasures require it to open them and get their xp.
Also probably worth mentioning since I am Alliance I pick up treasures in SMV, no idea how the treasure situation is in Frostfire but SMV there are tons and they are tightly packed together, especially at a place like the burial grounds where there are ~10 treasures in one fairly tiny space.