Hi John,
Maybe first check to see if Hamish's script allows you to input the information you are looking at for your project. (He did a pretty nice job)
Hi John, also there is a plug-in which you can install which can read in a text file with one x,y point per line and build a curve out of it. It can build either a polyline, an interpolated smooth curve which is forced to pass directly through the points or a control point curve which will use the point as the control polygon hull for the curve which will make for a kind of smoothing effect.