The NLC questline for the dep star gives good xp iirc, i know some people repeat the lucky charm portion. Getting the toe/HH head is a different story though
For the ones under 50m to make you can try antellion miter or tiger’s fang. There is also glitter glove which you can try to sell to make profit or money back! Only need to make the manual to get the exp
sorry about coming here late cpq2 is not that fast compared to goby leech, to be honest. I've tried "the fastest way" several months ago with 3 mules for goby (lv50 warrior, lv56 IL and lv61 IL) and 1 mule for ulu2 (lv70 IL). For your reference, lv45-lv65 took me 5 hours (goby leech) and lv65-lv75 took me 200 minutes (ulu2 leech). For lv105-lv120, I was hunting BF while buying petri leech (about 4.5 hours?). In this way, it took me totally 24 hours for lv1-lv120.
They are needed for lv50-70 because low level leech is so ineffective. lv70 IL with all buffs is strong enough to leech there. It's about 2 times faster than general WR leech. (To make it clearer, it's almost the same as SB leech for lv65-75 if your mage gears are very great!) btw, you can make a Chief Bandit to kill BF while buying leech after lv75. I believe it's the fastest way you want in RMS now (from lv45 to lv120).