Modern software is organized into applications which each host their own data and computational tools; users have limited ways to compose behavior across application boundaries. These limits are particularly apparent in tasks like travel planning, which require coordinating information across multiple tools in unique ways tailored to a specific trip.

We present a prototype called Embark which enables users to perform an entire travel planning process within a single outline document enriched with computational tools. In Embark, users can mix freeform text together with references to external data, and can author dynamic formulas for pulling in information like weather forecasts and routing information.

We find that Embark supports a wide variety of travel use cases ranging from short weekend trips to sprawling RV roadtrips, all within a single medium. More broadly, our work proposes an approach to unbundling apps into data, computations, and views which can be flexibly composed by users to meet their unique goals.