>>510253953 (OP)>There's a literal alien mothership heading towards Earth at startling speedsLaughably ridiculous notion. The universe is constructed in such a way that it is nearly impossible to travel any significant distance - even the most generous lending of optimism hits a hardwall of nope once any problems are examined in detail.
In effect, non-local interstellar travel is almost entirely pointless. Whatever has attracted your attention has no grantee of even existing once you arrive, and it's incredibly dangerous as you have no way to predict the space conditions in that 100,000 window, you'd have to store an impossible amount of energy, predict space weather 100,000 years in advance across the entire trajectory with <1 micron size particles with 100% accuracy while accepting the fact that it would likely be impossible to return and to expect 100,000 years to have passed in the universe relative to you once you reach the destination
There are ways of doing it, but trust me nobody's going on a fucking kayak voyage across the cosmos, you can fold, well, and jump but you cannot sail, anon.