So I hear that maglev trains are able to go up to hundreds of kilometres an hour. How quickly would they tend to approach such speeds, given the forces acting on the passengers due to acceleration? Would strong force over short time interval, or weak force over long time interval, be the preferred approach? Also, if they were about to round a turn at hundreds of kilometres an hour, would they slow down first, and if so for how long?

I think you'd have accelerations like in today's fast trains like the ICE or TGV (which is a soft acceleration, in case you've never been in a fast train) and only (if at all) a higher top speed. After all, you want the travel to stay comfortable for the passengers. You could try to look up the accelerations of said trains and calculate (an estimate for) the stopping process for a maglev train of your choice's top speed from that.