Well I started over since a week, and in 2 days I managed to make me a 2m in f2p. So I mean everything is possible. I personally just flip Chaos runes, swordfishes, rune legs sometime, really it depends. Minning iron in Fally is 200k/hour and it is not even that boring!
Another cool thing to do is buy loads of raw tunas, cook them, and sell them (they sell for 20 gp more), so it's basicly free cooking xp.