If you want a really hacky version, then if you didn't save Barcus Wroot, he should be dead by the windmill in Blighted Village by the time you get to Grymforge. You can push his body to the Underdark through the Spider Lair. Then raise him with Glut, and he'll act like you saved him. Then both he, and the character he is attached to, will teleport to Grymforge. You can then go and find the waypoint.
Nice, this is some funny way to exploit abilities and spells to break the game.
Good to know for future Speedruns, if pushing that body isnt taking too much timeeffort

What if there would be a way to make Glut beeing revived too, after having him killed and then takin him up to surfaceworld using his abilities.
Reviving Arka to solve the puzzle why shes dead before the goblin camp, or just revive the whole Goblinparty who attacked the grove a start. Ahh, so many options.
The possibillities would be endless, haha, great!.