mutool is great. You can install it portable as regular user on Windows, for instance. If you need to extract a few pages from a long pdf you can use mutool clean. However by default, this will create a pdf that is as big as the original input file. To compact the resulting file, make use of the -g options. So this works great to extract pages 19-20:

mutool clean -ggg  input.pdf output.pdf 19,20