I mostly been into mini-z's for the past two years. But I finally bought some bits for the kids for christmas and I was looking at the site above at the track pieces. I think its workable to print out on card stock, if that is still to weak you can reinforce the inside with some scrap pieces or the backs on the curves. I would use pieces at 90 degrees.
I know this is not "rocket sceince", even if all the gluing remindes me of model rockets
.