Healing set evolves a bunch as you go up, because there are a lot of new healing tools at high levels for druids. When you get Reptile, that gets a slot. When you get Adrenaline, that gets a slot. When you get Survival, that gets a slot. When you get Promised heal, that gets a slot. You'll definitely need both of the Mnemonic Retention AA for that spell set.
The basics of a support setup are one maybe two damage spells, whatever's most efficient. At level 71 that's probably Solstice Strike, but will be Winter's Flame at 73. Nature's Blazing Wrath (lv75) is the other dps spell I see druids still using a lot while in support role. Two, maybe three if it's a slow killing group, Atk debuffs, starting with Hand of Ro and Sun's Corona (upgrade to Hoar Frost at 74), adding Fixation of Ro if practical. Pretty much all the rest of the slots are heal spells. Reptile, Moonshadow, Chlorotrope. Adrenaline when you get to 75. Survival at 78. Promised at 82. Yes, that's six healing tools when you get all the way up there.
Moonshadow is probably the most replaceable of them in normal exp groups, if you need Spore Spiral or Harmony or a cure up. Karana's Renewal is usable for efficiency's sake for a long time, but is solidly obsolete in my opinion (just too slow) by level 80. Being a good druid healer is all about using the tools that are there. Reptile tank before you see the mob, get atk debuffs in, use the efficient heals as much as possible. If you try to just Chloro and med like you're a cleric, you will fall behind and look like you suck... because you will.
Soloing can mean two things, either kiting or charming. Charming is WAY more efficient and powerful for gaining exp, but your options for what content to do are limited, since it basically has to be animals. Hauling around a shm for their animal-ifying spell is not, as the British would say, "on". Glamour of Tunare, Ensnare (Entrap AA), Nature's Beckon, self invis (camo AA), one nuke for finishing the mobs (Winter's Flame again), lots of skill. A if you're really feeling your oats. It makes better exp, but more challenging timing to break charm at the right time for full exp.
Kiting takes about infinitely more mana and is way slower, but you can do it anywhere, like if you need to for loot or quests or whatnot. Ensnare, best dots, best nuke.