Not to sure about thieving,but for fletching, just shop down the best trees you can make into bows, and when you get to willows, just buy those or cut untill lvl 70 fletching. For herblore, you can try chaos druids in edgeville dugeon, bring like 3 items and fight them, and fill up your inventory with herbs. Keep the ones that you can't idenify for later or sell them for 1k each. EDIT:A good place to get willows is world in f2p draynor bank, buy for 25-30gp each. You can also raid general stores and get willows for about 16 or so gp each, but that method is mostly for firemaking exp.