Have a look at the simple inference of time dilation. What actually happens when you move fast on a round trip through space is that all your macroscopic motion reduces local motion. If you could travel at 99.99999999% of the speed of light there's hardly any local motion left, so it's a bit like being in the "no motion" stasis box. But there are practical problem,s like you hit stuff. And it takes a lot of energy to accelerate then decelerate. The best practical way to "travel to the future" would be via cryogenics. After all, we can freeze embryos now, so one day we'll maybe be able to freeze and defrost adults.