Many short story ideas I have involve space travel. I'm looking at the Lorentz transform formula and scratching my head. Is there a relatively straightforward way to use the time dilation formulae and calculate subjective travel times for space travel? Presume a spaceship accelerates at a=1g for the first half of its trip, and a=-1g for the second half, to stop at its destination. If the distance to its destination is d light years, how long does the trip take subjectively and how long does the trip take from stationary observer's PoV? OK, now what if I change a to, say, 2g?