I too share your view of gravity being a key for travel in that if one could reverse the polarity of the gravitational force or lock onto a gravitation force the enormity of the speed acceleration would be nearly instantaneous which could have implications for travel and communication. The polarity of the gravitation force is elusive in constructing an engine able to harness polarity frequencies. There would possibly be a bending or folding of time. If space could be left out of the bending or folding of time, then time would be insignificant as quantum mechanics states. Being here there and everywhere all at the same time to encompass the past, present and future and to view each event simultaneously would have our minds possibly so confused our minds would not be able to perceive what was actual in the past, present, or future. Each event would not take on its own distinguishing characteristics but would instead appear to be the present.
Einstein was a spooky person. His theories and equations and the understanding of such of Einstein's works are understood by only a few. I am not one of the few. Einstein's work is continually being dissected, in the present, and much of it may still be misunderstood (imho) though for myself, I never understood most of his works I read. Einstein was brilliant, and have heard it said he may not have been of this world.
“Our minds would not be able to perceive what was actual in the past present or future.” - Jim Beam does that to me. Jim Beam folds time.....wow.....bottoms up!