Best way to train now is to make augmentors. Before level 27, you can only get level 5 weapon. This will get you 108k exp once you dismantle. Because you will barely use this weapon, just do something cheap, a black salamander. Then once you get lvl 10 weapon, start doing a crystal staff augment and go camp Ganodermic beasts if you can. This is over 6m gp/hr and you will level your staff in 2-3 hours for 540k exp. If you want more exp, do ganodermic tops as well, but this will be costly. Once you get to level 45, you can do legs. Augment ganodermic legs and continue. Bring notepaper. Pick up all boots/gloves. Use demonhorn/bonecrusher/soul split. If you do not have soul split, use safespots because they are fat as hell.
I had a cannon on me but did not use it for this. This was a 1 hour trip. Worth about 7m gp.
Augmentor (45 Base parts, 45 Tensile parts, 45 Flexible parts, 8 Enhancing components, 7 Powerful components and varying amounts of divination energy dependent on the type used)
Base parts - white knight store, buy hilt stuff/shield. If impatient, royal/ascension bolts.
Tensile - yew sheildbow
Flexible - see Powerful
Enhancing - buy 600 slayer gems per day, 300 from canifis and 300 from taverly. turn into slayer rings and dismantle them. You get enough for 7 augments a day this way.
Powerful - Pouches, moss titans were good last I saw. Try finding a lvl 75+ pouch that costs under 6k, or do some yak/steel scrolls.
When you do slayer rings, you will get precious parts as well. Buy red salamanders (5k or so each) and break them down for dexstrous. Simple components can be found doing gold bars. You can make 2-3 siphons a day and they sell for over 2m each at the moment and this takes under 30 minutes.
Cost of an augment:
100k for base/450k if bolts
100k for tensile
600k for powerful
free for enhancing
black sally = 10k, crystal weapons = 900k
Lasts 2 hours if good at ganos, so 12m GP made from an augmented weapon
Profit = 10m gp and 540k invention exp in 2 hours
Cost of equipment siphon
400k for dexstrous
30k for gold bars
free for precious
Profit = ~4m/day