Don't care whether I can retrieve my arrows or not, just name some good spots please.

Ahem... Read, the range skill guide before you ask questions, skill guides are there to help you know.

guards up top of varrock castle

I heard Fortress Guards at Black Knight Castle is good too.

The ranged guide probably has better advice than me but here goes:

 

 

 

Lesser demons and moss giants on crandor and Scorpions in Al-Kharid mine. Personally I would reccommend the moss giants because they have respectable drops and, most importantly, drop big bones which are invaluble in raising your prayer, especially if you're F2P.