I made it to 100 without any boost so it's practically possible, but filling up a keepnet with gudgeons will not work. There are definitely strong diminishing returns on repeating the same action with skillups.
What worked for me was finding a rotation of different baitfish in different lakes (and one of them probably has to be a night time fish), so when you get a point, you move to the next lake.
Mine was this one:
Gudgeon, Rivulet, usual spots, size 22, Garlic
Bleak, Belaya, north section left side, 22, Fly
Ruffe, Kuori, anywhere at night, 24, Worm (not that good now)
W-Bream, Mosquito, pier, 24, Worm (just bad now)
All of them with 5kg invisible mono. I also tried to keep 3 Imperial buffs up while crafting.