You can rest in the Hag's House, just not in the plant trap maze. Not that it matters, because if you're smart, you backstab Ethel out of combat with one character, and then proceed to do the same with the other 3 characters for 4 separate surprise attacks that give you 2 free starting turns per character, or 8 total actions before Ethel can react. If you can't kill Ethel with 8 total actions, you either went in severely underleveled, or you are just playing completely suboptimal builds. Killing Ethel clears her entire house of the curse and deactivates the plant traps. Obviously before visiting Ethel, you want to kill the Redcaps outside; just get on a high ground mound and since their mobility is bad, you can get several surprise attacks in from high ground and just burn down each redcap one by one as they reach you.
Either way, the goblin camp is not hard. Outside, you can first take out with a single 100% crit on the sleeping mobs up top as sleeping mobs are automatically crit, so a single Lazael auto one shots them, and then you take out the 2 bugbears easily without aggroing the camp.
You then go and save, poison the cauldron, pass the dialogue check so you don't drink the poison with them, it wipes out half their camp and leaves the other remaining Goblins at like 6-7 health, and then you climb up to the stone bridge above, surprise attack the mage up top and kill him, and simply snipe down the remaining force as none of them can reach you besides the ogre throwing javelins at you, so you focus him first.
Inside, you tell the hag whatever dialogue you want, follow her to her room, kill her in private with a single surprise attack in the first turn before she calls help (just do a Lazael Frightening Strike from backstab stealth, or select the dialogue where you tell her you are killing her and if you roll initiative well, you go before her).
You then go talk to Razglin, pass the dialogue check to sabotage him (or don't talk to him and save him for last), go to Minthara and easily kill her alone with the 2 other goblins; if you kill the archer first, nobody rings the drums for help. Then you go back to the central room and get up the ladders to the roof and start sniping the goblins from high ground; they'll miss most crap on you and die trivially. Make sure to talk to Spike with Wyll and kill him alone with the other goblin easily.
All in all, that route lets you go rescue Halsin, bring him to Razglin's chamber and fight at most like 10-12 goblins, and they're separated by a wall and door if you know how to use LOS to your advantage hiding by Minthara's room, let the melee trickle to you and you kill them easily before Razglin's room; when fighting Razglin himself, bumrush him to kill him asap as it removes the aura of leadership off his allies; clean up the rest easy.
By far the hardest fight in the game is Bulette if you don't cheese him, followed by Githyanki patrol.
It's great that you all know this, but people won't know it at the first playthrough, so many of these fights will be difficult for them. However, I do not consider a fight with a goblins to be such, they just have little HP. Also, about "hag's dungeon" I meant the underground part, because it is closed. That's the difference. By going there, you "load" another area. And don't forget about spider, first time it was a very difficult fight for me.