Id just say do it however you'd like, Each person plays the game differently, some are questers, diary hunters, pets, etc.
If you want I am always willing to give advice or suggestions for certain things, so always feel free to shoot me a message or anything that I could possibly do to help you out.
I enjoy quests, but the quests need to have a useful aspect or a benefit to my account, there are quite a few quests that are just annoying, maybe make a goal of like 1 quest per day or something
As for combats, Dwarf cannon (i know quest....) takes about 8 minutes, pretty easy to do, can easily do 40-50 range in less than a hour or two, if you dont wanna go that route, pick up some iron knives (for 20 range) then do mithril darts. Rock crabs are decent (Fremmy) or Sand Crabs are pretty good too (Zeah)
Problem with both rock/sand crabs with your lower stats and defence you probably will get hit semi-regularly so it wont be as AFK until maybe 20-30 defence.
Melees are pretty simple, either questing and doing Waterfall (att/str xp), Witches House (HP XP), Fight Arena (att xp), tree gnome village (att xp), Grand tree (agi/mage/att xp?) and a couple other random quests will definitely help but if u dont want to do that maybe mix it up with using the Slayer Master Tureal out in Burthope and that might give u a little incentive to use a couple different combats and find out which styles you like.
Later On I suggest using a Magic Shortbow for range, at 50 range which is really cost efficient, toss some addy or rune arrows on it and its really afk to do most combats especially if you have an Accumilator from Animal Magnetism which will pick your arrows up for you.
Please let me know if u have any more questions, feel free to PM me whenever, my Inbox is always open and I can and will always be willing to help you out