Barrows RuneScape 2107 gold gear is great, but if you die, the things degrade to 0, and repairing becomes expensive. I would suggest looking into Dragonrider gear; it is hybrid (meaning you can use it while coaching all three combat styles) and the whole set provides a prayer bonus of +46 roughly.
The Elder Kiln gives you the Tokkul-Zo ring, capable of teleporting you straight to a lender and a fairy ring. If you really do Fairy Tale part 3 as well as The Elder Kiln, you can reach most areas in RuneScape within minutes. I'd say finish Shilo Village and go to Duradel. When you strike 75 slayer, visit Kuradal in the Ancient Cavern, and then proceed to Morvran for your final few levels. In terms of herbs, I believe RuneScape Wiki includes a spreadsheet with the best herb to now do. Normally, snapdragons, toadflax and ranarr are safe choices.
I suggest you focus on Slayer for the time being; it is profitable (more so at higher levels, but still rewarding ) and you train the majority of your skills while slaying. Also, I suggest obtaining 80 dungeoneering for a Chaotic. Until then, try to get 70 attack for a Whip. Last, I suggest that you do some quests today. A good deal of your abilities are reduced, and the xp rewards will help you skip some instruction. And glad to hear you've got membership!
Barrows is tier 70 tank armor, so it is somewhat on accord with GWD armor. Barrows supplies more defensive boosts whereas GWD provides offensive boosts. I'd avoid using barrows for normal slayer as it is not likely to be worth the repairs. Dragon rider is really expensive, and you merely have 4m to spend. You should be fine with range since dragonhide is cheap (Royal is grade 65, prices maybe 30k for whole set?) Kuradel - 75 Slayer, Ancient Cavern (the one with Mithril Dragons) along with the brand buy OSRS gold new: Morvan - 85 Slayer, Prifddinas. Will take a while.