I don't think that will work....in space thee is no gravity.....but a lot of gravity waves crisscrossing the universe....
just need a way to hitch a ride on them.
Just because you can't see it, doesn't mean it isn't there! (Playing devil's advocate here, a lot of this stuff is conjecture.) Scientists are puzzled that the amount of known matter in the universe doesn't explain the after-effects of the Big Bang, how fast galaxies are moving away from each other and the speed of expansion of the universe. They explain it by accounting for the missing matter as dark matter. It is everywhere in the universe, although invisible to us, and imparts gravitational fields everywhere. So... just hitch a ride on a big hunk of dark matter and propel your vehicle anywhere!
Not just gravity waves, remember ALL waves extend to infinity by definition.
However, with waves emanating from all directions, and diminishing in amplitude with distance, they are all going to be interfering with each other at a small scale at any particular point in space, and probably just creating some little barely perceptible local fluctuations, not some ocean-type wave that we could ride on.