\usepackage{fontspec} and you're done. \setmainfont{Palatino Linotype} to just use that, \newfontfamily\secondary{Times New Roman} now you can just stick in {\f

\usepackage{fontspec} and you're done. \setmainfont{Palatino Linotype} to just use that, \newfontfamily\secondary{Times New Roman} now you can just stick in {\fontspec{\secondary} blah blah blah} for bits you need styled in a different font for a few words/sentences/paragraphs/however much you need. And if you need the automatic TeX style replacements (like turning `` into opening quotes - personally, I hate that, I'm writing text, not programming - then you can pass in TeX mapping instructions in [...] blocks, covered by the fontspec manual: \setmainfont[Ligatures=TeX]{Font By Name} and \newfontfamily\whateveryoucallit{Font by Name}[Ligatures=TeX])