Around 1hour of exp to 62 is required:
To lvl 35 you kill 1 worm.
After 35 you can either head to luferson/emc and kill lycans dire zombies skeleton familly mobs they all give same exp, solo without premium 90k
or to cz: Burning skeletons, blood seekers these give 160k solo
Deruvish gives: 320k solo
Best exp is harpies and trolls or golems 600k+ solo without premium.
800k exp required for each level between 50-54
Then you need 8 milion exp from 54 - 55
Back to 800k per kill till 55-60
60-61 8 milion again
and 61-62 10 milion with reduced exp penalty.
All together is around 1h max, I solo exped to 62 in 40 minutes, but my archer combo is godlike bbbbbbbbbbb xD
When expansions take place it's gonna be like: