If you knew you were going extra-solar, you would want to pick guide stars with minimal/immeasurable parallax over the scale traveled. A naive worst case scenar

If you knew you were going extra-solar, you would want to pick guide stars with minimal/immeasurable parallax over the scale traveled. A naive worst case scenario would be not negligible. For example, Proxima Centuri has a measured stellar parallax (from Earth - so across a 2AU distance) of ~0.8 arcseconds. We were able to measure that parallex from the ground by the mid 19th century. Abusing small angle approximations, that implies that each ~arcsecond of shift you encounter could potentially mislocate you by ~2AU...