Well, rather than bring your
fuel along, why not get it as you go.
This Bussard Interstellar Ramjet concept, from the 1960ís, relies on scooping
up the lonely protons that drift in interstellar space, and then somehow
getting them to fuse to make a nuclear rocket. There are a variety of limitations
to this concept, such as how many protons can be scooped up, the drag created
from scooping them, and, not to mention, the feat of getting these protons
to engage in nuclear fusion
for a rocket.