If you're able to do the Swan Song quest, definitely go for monks (profit). In comparison between trout/salmon and monks in terms of xp, there is not too much of a difference iirc :)
If you're wanting to make a profit, nature runes are the way to go - preferably through the abyss. If you're looking for speed I'd go along with fires/airs and possibly laws when you reach that level. Good luck ;)
I'd recommend to do slayer too. I'm about the same level as you and now I'm starting to wish I'd done more slayer tasks before this level. You could also go to the third floor in the Stronghold of Security and kill some of the red spiders which are aggressive and give great exp. Good luck :)