Tethers are an underutilized tool in multi-robot systems: tethers can provide power, facilitate retrieval and sensing, and be used to manipulate and gather objects. Starting with the simplest possible configuration, our work explores how agents linked in series by flexible, passive, fixed-length tethers, can use those tethers as sensors to achieve distributed formation control. In this study, we extend upon previous work to show the applicability of strain-coordinated formation control for encapsulation and migration along a global gradient as well as the trade-offs between formation control and taxis in an obstacle-laden environment. Our results indicate significant potential for tethered robot collectives: versatile behaviors that can work on simple, resource-constrained robots or serve as a fallback mechanism in case more sophisticated means of coordination fail.