Relativity is our friend. If you can get to a high-enough fraction of c, from the traveller's perspective most trips would only last a few months. I can envision a scenario where the spacecraft is accelerated at 1G, coasts at a very high speed, then turns around and decelerates at 1G to the destination. This would provide gravity for most of the trip, with the zero-g portion of the trip being very brief for the travellers.
Not particularly. The problem with traveling at significant fractions of c is that mass also increases as you get closer to c.
The relativistic "benefits" to interstellar travel only begin to be tangible at very high percentages of c.
I don't have the exact figures in front of me, but for instance, even 90% of light speed produces no significant relativistic benefit WRT such travel. More like 95-98% of light speed, or even higher, is needed, and with the attendant increase in mass, more and more energy is required to gain even the smallest amount of additional speed.
It'd be great if we could somehow propel spacecraft to 98%+ of light speed, but such science is not within our grasp for the foreseeable future.
It will truly take a Zephraim Cochran-like breakthrough in order for single generation interstellar travel to become feasible...
Sub light opens us the solar system, not interstellar space. If you figure out how to do suspended animation with sub light, then it’s possible.
bottom line, we are sometime away from it, we’ll eventually get their, but only the youngest of us may have kids to see it.