Heat the vegetable oil in a large, heavy-bottomed pot over medium heat. Add 2–3 popcorn kernels, cover, and wait until they pop, 2–3 minutes.
Add the remaining popcorn kernels in an even layer, cover, and gently shake the pot to coat them in oil. Reduce the heat slightly to medium-low.
Cook, shaking the pot occasionally, until the popping slows to about 2 seconds between pops, 3–5 minutes. Remove from the heat immediately.
Carefully transfer the hot popcorn to a large mixing bowl, leaving any unpopped kernels in the pot. Sprinkle the salt over the warm popcorn and toss to season evenly.
In a small bowl, whisk together the melted butter, ground cinnamon, and brown sugar until the sugar is mostly dissolved and the mixture is smooth.
Drizzle the cinnamon-brown sugar butter over the warm popcorn. Toss gently with a large spoon or clean hands until the popcorn is lightly and evenly coated.
Add the salted roasted peanuts, chopped roasted almonds, raisins, dried cranberries, and lightly crushed mini pretzels to the bowl with the popcorn.
Toss the mixture gently until the nuts, dried fruit, and pretzels are well distributed throughout the popcorn. Let the mix cool to just barely warm, 5–10 minutes, so the chocolate will not melt.
Add the chocolate candies and toss briefly to combine, being careful not to crush them.
Serve the popcorn trail mix right away in bowls, or transfer it to an airtight container. Store at room temperature for up to 3 days, stirring or shaking before serving to redistribute any settled ingredients.