> address for the WebVacuum)  Can I install HTTRACK on my
> portable drive and use it on whatever computer the
> drive is plugged into?
Sure.  Download the ZIP package of HTTrack and extract it onto your portable
drive.  It should run from there on most computers.

Then when you create your project set the "Base path" to point to your drive. 
So if it's mounted as drive G:\ then use something like G:\My Web Sites
and HTTrack will save the project there.