Sounds a day's guildleves give you enough SP to level a class

[Rydin]

i got 27-37 before they fix the SP gain in the last Patch in about 1week or so. All we did is pick up the leves that give the most SP when you about to get it done stop and return back to the crystal and cancel it. Next level reset you have the same leves again and again. So now with the new SP? i get 1 level per day doing the good leves x2 with my gf which so far i got 39-44 about every leve reset i got a level or 90% of it. so if you have a linkshell and you do leve link and have a lot of players you could easy get 1-50 in 1 and half weeks.

with no grinding.. I don't know... 2 weeks is even pushing it....
45-50 you'll get 1 level or less per reset... and even if you got 1 full level per reset, thats 1 week by itself (5 resets equal 7.5 days)
and you definitely can't get 1-45 in 3 days