It's not that bad, I just leveled up 2 mules partly for this purpose, 1 miner, 1 botanist. It took 4 weeks, I'd estimate 50 hours total each.

-To start it's a few hours to progress through Ifrit and join a GC. Daily turn ins and seals for ventures (the main reason for the mules)
-Every day, low level duty roulette (never unlock further dungeons, they take too long) and turn in of DoH GC items. approx 40 minutes
-Every 5 levels of DoW/DoM, unlock leve zone and do DoL leves, and next quest in class story line. approx 1-2 hours per week
-Send retainers on 18 hour ventures, keep them close to your DoL

Gear for them was fairly inexpensive, min melded to hit HQ on 2 stars doesn't require overmelds, or the 2.3 accessories. GP is over 550, so I can round up 25 darksteel/gold/crawler at a time.