Also, I suggest getting 80 dungeoneering for a Chaotic. For now, try to get 70 attack for the Whip. Lastly, I recommend you complete some quests today. Many of your abilities aren't that great, and the points you earn from OSRS Gold xp can help you avoid some of the training. Glad to know that you're a member!

Barrows is armor for tanks of tier 70 It's also in the same lines as GWD armor. Barrows offers more defensive boosts however GWD offers offensive boosts. I'd avoid using the barrows in normal slayers since it's not worthwhile to make the repairs.

Dragon Rider is quite costly but you have only $4m available. I think you can stick with the tier 50 melee and mage armors currently (Rune, Batwing) because the tier 60 ones (dragon infinity, dragon) are a bit of an increase in cost. You should be fine with prices since dragonhide isn't expensive (Royal can be tier 65 and costs about 30k for the entire set?)

Slayer Masters include: Duradel/Lapalok Slayer Level 50, Shilo Village. Kuradel - 75 Slayer, Ancient Cavern (the variant with Mithril Dragons) and the new version: Morvan 85 Slayer Prifddinas. This requires Plague's end, which requires 11 levels of 75 skills as well as lots of quests. Will take some time

2h Weapons and dual wield is the best option currently. Use shields only for slaying hard tasks or dragons (if you don't have Antifire Pots). If I were you, I'd buy a dspear for a low cost melee weapon of tier 60 (you could also go for dual-wield dlongs and dscims). If you're a mage, try an adventure in Mage Arena (in the wilderness) and Cheap RS 2007 Gold buy a god staff. For range, get an elder shortbow. That's all I can think of.