You tried varrock dungeon ?
rats , zombies , skeletons , ghosts , scorpions , spiders , giant moss.
Rats are lvl 6 , you can train there , ghosts , skeletons and zombies are accesible too.
I used to train on men in edge lol
I do believe he meant definitely
And yeah, PC is a good place to train too once you have membs, though rock crabs is comparable until the higher levels I hear.