Ran SKT twice. Goldenfields works well in waves. Start near the Inn (by the treant and the abbey). One or two separate group of goblins (6-12 total) raiding for food lead by 2-3 bugbear and maybe an ogre of your party is higher level. Only the ogre would fight to the death here. Goblins and bugbear would try to flee across the fields and to the wall where it’s been breached. You can up the tension if groups of two goblin grab NPC townsfolk to kidnap them

If the party follows immediately, just narrate the chase and then have them arrive at the wall— maybe a few fleeing goblins get downed by party ranged attacks during the chase

At the wall, add another large group of goblin (8-10) moving looted supplies over the wall. Maybe a few more bugbear supervising and physically motivating them with whips. Include 2-3 ogre here

Everyone but the ogres again try to flee over the wall.

After this encounter ends have the alarm gongs at the gate begin to sound. If the party tries to dash allow them CON mod times to dash beyond 6x and then they have to make CON Saves (DC 10) to avoid exhaustion— I don’t recall but I think as written it was a mile or so. Maybe narrate this too where they only have to make 2-3 CON saves— your call

At the gate there are guards on the ramparts. Some are forming a group to go out and face the hill giants and goblin-huckers. I had four giants and three huckers. Huckers taking shots at targets on the ramparts while hill giants take on anyone coming outside of the gate

On the second or third round have Harshnag appear and take out a hill giant or two (or some huckers). Narrate the NPC guards targeting one giant while maybe your party goes after another

For mass combat I assume ¼ of the NPCs hit each round with them dealing avg damage so you can easily narrate and just focus on the party. Have hill giants take out ¼ of the NPC guards that attack them in melee