I know I’m 15 years late to the party, but I just finished solo adventuring through the Hordes of the Underdark Neverwinter Nights module as an Arcane Archer, and as much as for my sake as anyone else’s, I wanted to catalogue my experience. This post will contain spoilers for the HotU story, as minimal as it is.
I chose a play as an Elf, with levels of 9 Cleric/1 Wizard/X Arcane Archer, with the Zen Archery feat. Essentially, I took the Wizard level as a throwaway level, since the armor I would choose as a Cleric would interfere with the Wizard’s Arcane spellcasting. You can question my build and offer your ideas on an Arcane Archer build, but the 9 Cleric levels gave me essentially all of the Cleric’s buffing spells, namely Battletide (Level 5 spell, which the Cleric will get at character Level 9), which really helped my PC throughout the campaign. I took the Earth and Healing Domains, though in hindsight, I could have dropped Earth for perhaps Trickery, as Earth lost its usefulness in the later stages.
I played under the Hardcore Rules Difficulty with Item Level Restrictions (ItemLevelRestrictions=1), so I couldn’t just make a beeline to Rizolvir to craft an über weapon at the start of Chapter 2. I also tried to avoid using potions and one-off spells as an additional challenge.
I started with (Str/Dex/Con/Int/Wis/Cha) 14/14/10/12/15/12 and ended at Level 28 with 14/14/10/12/24/12, having taken Great Wisdom II. I actually could have levelled up to Level 29 at the end, but wanted to see if I could finish the game at Level 28. At Level 29, I might have taken one more Level of Cleric, just for additional Level 5 spell slots for the final battle.
As soon as I started, I began to wonder if I had chosen poorly, because I had a tough time immediately upon the descent into the Undermountain in the first encounter with a group of Drow. But, I eventually defeated that group with the help of the Dismissal and Invisibility Purge spells and the character began to grow in power. I didn’t really have trouble with any other encounter in Chapters 1 and 2, save for the Isle of the Maker’s Mithral Golems, which I left at level 21 and defeated upon a subsequent visit around Level 23. Though I used Assanti as soon as I obtained it, I had purchased a Longarm bow early and after upgrading it with Rizolvir, I used it especially to defeat enemies with resistance to Piercing damage (e.g. the Maker, and the Undead).
In Chapter 3, I switched to a regular Longbow, with a +9 Attack Bonus, and Mighty +8 (which I bought from Rizolvir’s Ghost, then upgraded). But, I still had great difficulty with the Grimgnaw’s posse and the big boss, Mephistopholes himself.
With the Long Death (Grimgnaw’s) group, I eventually had to use two Potions of Heal and targeted Crimson first, to avoid her Bolts of Dispelling, then Koth Uth-Kalin (the Minotaur), then Blapheron, then Maugrim, then Grimgnaw.
With Mephistopholes, though I had sufficient resistance or immunity to both Fire and Cold damage, I had to use around ten Potions of Heal because his Trident and Ranseur would wreck me. (Does he use both, or just one? I don’t quite know.) Had I been planning better, I would have bought a Greater Archer’s Belt from Argali in Chapter 1 or Rizolvir in Chapter 2, because when I cheated to give myself one, I found that I could stand toe-to-toe with Mephisto easily. Also, I could have used the Invisible Death Armor that I looted from Crimson to cast Improved Invisibility upon myself before teleporting back to Waterdeep for greater survivability.
It was a challenging and enjoyable endeavor, and my record here may help you or me in subsequent Arcane Archer playthroughs, which different things to tweak or try. If you have any questions, I will try to answer them, and if you want to tell me that I’m an idiot for neglecting some item or Feat or game mechanic, you can do that as well.