You really have 3 options when it comes to your visible slots, and all three are going to require grouping with others to accomplish them.
1) Cultural + bazu/LB - This will net you the 2nd most total hp, the most ac, and the least heroics (but not too far off on the heroics that matter most) - shyra is obviously the easy target for bazu's, and at 80-85, is exceedingly easy, but like any possible target, no mercs can be used, you will also have to shell out the most cash to make this unless you are a tradeskiller than can make the parts yourself
2) SoF Tier3/4 gear - This will net you the least ac, the second most heroics, and the least hp - if you can get crystallos keyed and get a couple of friends to dedicate some time to farm cores and then camp crystallos, this would be the fastest route to gear probably, you also get the bonus of being able to camp some ac augs at various stops along the way
3) SoD gear - This will net you the second most ac, the most hp, and the most heroics - but the mods are horrible and will require careful planning on accessory gear and probably sacrificing some ac augs for avoidance augs - the bonus with this, is its more current and probably a lot easier to get people to camp the stuff with you, because people are already camping the stuff - its also the cheapest - BUT, you'd have to level to 85 to take advantage of most of the good gear and you're aa exp rate will suffer greatly if you are soloing anywhere for aa exp
You pretty much need to pick one path and work on it, mixing and matching will waste your time, and there really isn't any bazaar options or dropped single piece gear to replace any of that with. I'd suggest doing SoD gear, grinding whatever aa you think are essential to get, then grind to 85.
For augs though, here's the suggestions:
1) Blessed Shard (Yxxta) This one is only if you ever get a piece of slot 8 gear or SOE wises up and gets rid of the 7/8 distinction, very easy, you + merc could kill the lizard and insect probably
2) Mechanic Guardian augs - Fragment of Heavy Steamwork Plating - random drop from ANY mob in zone, you can easily solo the lower levels with you + merc healer, as its random, it might take awhile, but its something you can do by yourself, Colepotera Mechanical Beetle Eye - this drops from a named on the top floor, and you'd pretty much need a couple people to camp it with you with your gear level , BUT, its really solid experience in a fully group, so make a group, kill the whole top floor, and hope the fragment aug drops from a random mob while camping the other ac aug
3) Bayle's Heraldic Crest + Blood of the Fallen - both of these are solid quest augs, and are not hard to do, just take awhile, but you get faction for the new expansion which you need anyway
4) Fabled Fire Idol - don't worry about this now, but keep it in mind, because when fabled comes around, you might still could use it and its super easy, just can take some people awhile to have it dropped
5) Crest of the Scarlet Legion - if you're smart, you might could do this with just you + cleric merc, but get a friend to help so you don't have to worry, this is the ashengate aug - the mob is like, 10 mobs from zone in, and there is no reason not to camp it
6) Forged Frosteel Ingot - This aug is even easier to camp than the ashengate one, break the camp and just camp it till it drops
7) Illslan Enforcer Medal - Very easy to do now, pretty much a joke, just grab some people and run through the mission quick, its an autoreward, so don't even have to rely on the rng
SoD augs - the 30 ac augs from kaesora you'd probably need to be leaching in a group pretty much, but you can probably get in a group camping FoS and get the two 25 ac augs there, which have good hp on them.
I'd work on those as you can, stuff like geartop and sparkbolt will require a lot meatier tank than you, but if you can get a good group there, you can get steam cores for crystallos visible gear.