Fonts & Character Sets ⇒ OT Fonts for XeLaTeX on portable TeX System

[Laurentius]

I sometimes use a portable MiKTeX, and I was wondering if it is possible to install open type fonts into it, that is, not into the local machine (where there may be restrictions against it, apart from it being unpractical having to install anew for each new machine). I know that one can use square brackets and specify the otf-file instead of an installed font in \fontspec, but the odd thing about that is that is seems to require that it be in the same directory as the document. [..\doc\caslon.otf] does not work. I would be more than happy to use "[caslon.otf]" instead of "Adobe Caslon Pro" if only I could get xelatex to look for it somewhere else.