Upscaling is just making frame bigger. Sharpening is just making frame sharper.
Smoothness shouldn't hurt from them. So anything that works for you is fine.
For sharpening videos, there are several sharpeners you can use. For example: lsfmod(), fft3dfilter(bt=-1, sharpen=0.3), nonlinusm(), fqrestore() -
my favourite, or use just sharpen().
Here is the list of some sharpeners
http://avisynth.nl/index.php/Externa...ers#Sharpeners