Wow. Amazing job camping Aviansies/Gargs and making that cash money Definitely get 70 prayer w/ Piety, that's a major advantage for Pk trips. The questline gives you a fair amount of combat and prayer xp, so it's well worth the time.
Don't let the other quests overwhelm you! Focus on completing DT, and just get rune gloves. No need to rush for Barrows Gloves. If you need any help with DT let me know! It's not bad at all.
As for Agility, you might want to use some lamps. For runecrafting, make sure you do the Tears of Guthix quest and do the mini-game once a week for free xp. Really no reason to train RC too hard...
Keep it up!