I would say go to Flesh Crawlers on Lv2 of Stronghold secruity. (There's a room close to the entrace that isn't as popular as the others and has lots of giant rats) I go in full rune(can use runechain) with a sling and it's been doing nicely. I can stay for about 18hours before banking for more swordfish and pizza
The island where you do "Dragon Slayer quest" Moss giants/lesser demons there
should get you a decent amount of xp/h, still i suggest you to buy a memberpin and bot Druids or soulwars
If you have lots of arrows you can just camp in varrock sewers and kill the zombies that are there? They are an alright level with decent hp and you never need to bank since they are across the river.