Spacicles

If you take a tiny piece of earwax and drop it into a pint of lager, the froth disappears.
The reason is that the oil in the earwax breaks the surface tension of the froth's bubbles, and they collapse; as obviously, oil and water cannot mix.
Similarly, in order to facilitate traverse of spacicles quickly, we could stretch them into an artificial conduit.
Such a geometry is completely possible.
Consider if you will, two massive horizontal wheels, placed side by side traversing a small ocean crossing. One for travel in one direction, and the other, the other way.
Now imagine that they are "staggered," so that only the front half of the wheel is across the ocean in one direction, and the same the other way around so that each axis is on each shore of the ocean.
At high velocity, the areas across the ocean will contain stretched spacetime, which, furthermore; does not need to be stretched (maximum velocity c), but is stretched already. Bypassing the task of entering and exiting the streams, the speed obtainable is only limited to the limits of physical rotation.
But in order to go anywhere, we must develop a system for collapsing spacicles dynamically. The obvious candidate for a catalyst is matter, as; just as with the oil mentioned earlier, space and matter do not mix.
The tiny size of spacicles prohibits the use of ordinary matter, however.
The gravitron can produce super-dense materials, but even with complex modifications in the geometry, producing a symmetrical gravimetric wave is practically impossible. Even using a solid-state gravitron, the fluctuations between distances do not permit a perfect structure.
Furthermore, there needs to be a way to control the collapse of spacicles. If a mass were place in front of the leading edge, it would succeed in preventing any further collapse, but unfortunately the space between it and the masking plate would also collapse, causing the plate to fuse to the leading edge.
In the absence of any inhibitory device, the collapse will continue until it reaches a mass, upon which it will fuse itself to it rather messily.
Another approach is to use either a gelatinous substance, or variable geometry down on the atomic level, the alteration of which being just sufficient to suppress the continuation of further collapse.
The speed of collapse is faster than light, and according to the mathematical construct of the spacicle, which remains secret.
At this point, you may be thinking that travel for nothing defies the very laws of nature. But, we are beyond Newtonian physics, and are directly interacting with the fabric of the construct of very space itself, an almost wholly mathematical undertaking.