You can get a jump on the prep before you leave home. If you pack the chicken and shrimp frozen in your cooler, they'll keep longer.
1 small onion
1 green bell pepper
1 cup pimento-stuffed green olives
1/2 pound Spanish chorizo or andouille sausage
1 1/2 pounds boned, skinned chicken thighs
1 1/4 teaspoons kosher salt, divided
2 1/2 teaspoons smoked paprika, divided
3 tablespoons olive oil, divided
1 fennel bulb with feathery greens
3 large garlic cloves, minced
1/4 teaspoon saffron threads
1 can (14 1/2 oz.) diced tomatoes
2 cups Arborio rice
3/4 cup Spanish fino sherry or other dry sherry
1 can (14 1/2 oz.) reduced-sodium chicken broth
8 ounces thawed frozen shelled and deveined cooked small shrimp (70 to 110 per lb.)
How to Make It
Chop onion and bell pepper and put in an airtight container. Put olives in a container. Thinly slice chorizo and package airtight. Cut each chicken thigh into 3 pieces, toss with 1/2 tsp. each salt and paprika, and package airtight. Chill ingredients.
Heat 1 tbsp. oil in a 6-qt. pot over medium-high heat on a camp stove. Add chorizo and sauté until browned, about 5 minutes. Transfer to a plate with a slotted spoon.
Brown half of chicken at a time in pot, turning over once, until cooked through, 6 to 8 minutes per batch. Transfer to a second plate.
Meanwhile, trim ends from fennel and reserve feathery tops. Halve fennel lengthwise. Cut out core in a V and thinly slice bulb.
Add remaining 2 tbsp. oil to pot along with fennel, onion, and bell pepper. Sauté until fennel softens, 7 to 8 minutes. Stir in garlic, remaining 3/4 tsp. salt, remaining 2 tsp. paprika, and the saffron and cook until fragrant and sizzling, about 1 minute. Add tomatoes; cook, stirring, until thick, about 5 minutes.
Add rice and stir until coated, then stir in 1 cup water, the sherry, broth, olives, and chorizo. Cover and bring to a boil over high heat. Reduce heat and simmer until rice is tender and liquid is almost absorbed, about 25 minutes.
Arrange chicken with any juices and shrimp over rice. Cook, covered, until shrimp and chicken are hot, about 5 minutes. Chop fennel fronds and scatter on top.
Make ahead: Through step 1, up to 2 days, chilled.