Well, if we are considering camp and sleep (not necessarily both), I wanted to ask if any of you have some plans other than get Lord Torath aboard, sleep and return do dungeon.
If so please share.
I have few plans which I don't care much to dismiss if you vote against it:
1. Scouting:
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Through other planes:
So, I've discussed this option of using astral plane with TristenC few months ago and we got to conclusion that using the Ethereal plane is better described in the literature for such purpose (although it have other risks as I think there is also more literature about the Evils that dwell in the ethereal plane than the Evils on the astral plane. One thing that is remarkable on the astral plane is that it has no limit of time and range as you can instantly get anywhere, but other spells speak of "windows" to move between the planes, so it is not clear that you can use this as "teleportation" or not.) Anyhow there are few spells available to us to go through the ethereal plane I think at least for few hours. I think that Axid also have such psionic ability or something similar to plane shift.
By minions:
Can create moderate power undead and maybe skeletal bat but I'm not sure it is possible, and send them forward to scout (or even do some harm) the enemy.
Can summon elementals on daily basis (spells and magic item) and ask them to check the dungeon, fetch something from there, grant wishes etc.
(If you have usage for fire elementals, please share. I plane to summon one daily, even if just to light our campfire.)
By spells - there are more than a few divination spells, but I couldn't get good enough idea how to use them robustly for scouting.
2. Gather several minions
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Well, as any reasonable necromancer will tell you, many spells requires victims

. Since,
unfortunately, the people in the camp are not willing to be sacrificed, this way is more appropriate for dead monsters, but in camp Ke'Sha can summon undead daily and try to take control over them.
It is also possible to ask Elemental fetch you a monster from the dungeon, preferably humanoid, and use it for the spell or finding dead one, animating it and use it.
Allakhain can summon shadow or polymorph small creatures into undead. (Weird huh? But I haven't seen any restriction except the surviving system shock one).
Such minions can scout as mentioned before, be messengers with the camp, (maybe there is a different spell with long duration that can use for contact with the camp representative), and of course used to trigger traps
3. Diseases
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One spell forces a plague on large areas (like wiping cities), others can be sending minions with some source if infection and starting to infect other creatures (sneezing on them

)
4. Boosting
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There are few boosting spells that last for long times (days), although I failed yet to find good ones with some exceptions, but you may know of others:
Days long spells:
- Phantom armor
- Sacred guardian (17- team size days) - might be a bit useful if we split or to alert camp of danger, but assume we are constantly in danger

- Unfailed endurance - 17d
- I was sure Stoneskin is permanent until used, but I saw that there is DM option not in the PHB that limit it to 24h
- Contingency - Not sure if anyone have it but it can really save us all (auto protect mind on condition of mind targeting spells, or dispel darkness, or teleport back to camp on bad condition etc)
- Protection form fire/cold/... last until HP absorbed (only 12 HP if I'm not mistaken, but still...)
- Mask of Gargauth - 17d - can have wings which is good for many traps, falls, etc, can replace/aid AirWalk. Can be used for other forms that allows burrowing for example.
- Succor (permanent until used)
- Aerial servant (17d)
- Continual light (cast once and keep hidden of course)
- Permanency

- Persistence
- Mordenkainen's Magnificent Mansion
- Mass Invisibility
- Limited wish (few days at camp, using it daily can do MAGIC for us

) (usages - extend spell duration from few rounds to few days, such as Trolish fortitude, gaze reflection and similar)
- Etherealness
- Firetrap (as powerful grenades)
- Item
- Explosive Runes
- Protection from Hunger and Thirst
- Armor
24h/17h spells (stoneskin included) cast on the last night can boost the first day in action (not losing spell slots):
Stonesking
Cat's grace
Crocodile's tears
Astral awareness - not sure how helpful it is..
Endure cold/heat
Spectral senses
Von Gasik's Refusal (not sure any of us have access to it, but it is a good protection against spell caster. Locking the corridors of the dungeon to them)
Ultravision/Infravision
Evard's Black Tentacles (blocking the dungeon)
Strength
Protection From Cantrips
side note: 17d in game is about 34 year of PBP, which is as close to permanent as it gets.

I might have better chances surviving in game than surviving in real life.
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All these directions require few days at camp, in contrast to rest and straight back, so I get it if you are against it.
Please share your thoughts.
Thanks.)