Things you need:
1.) Level 135 FA. No more no less. <-- Must have descent set of perfect amp and weapons.
2.) Level 135+ char. <--- with or without set. doesn't matter
3.) Oath of sacrifice.
4.) Premium
5.) bb+
6.) 150% xp up
7.) Around 10 or more s1 entry for both chars.
8.) Cabalrider with AOE.
9.) Obviously, your brain.
If it's from level 1, It'll only take you about 2-3hrs leveling alone up to level 135.
From level 135 - 180, it will take you about 10-12hrs.
It's not going to take you 2-3 days. You only need a day from level 1-180.