First, read your owner's manual, it explicitly covers the use of chains. According to the manual for my 2003, you may use chains on the front wheels ONLY, and you must not exceed 19mph. Yours will probably say something similar, but please double check.
However, the general rule of Subaru AWD is: "All for one, and one for all." Whatever you do to one wheel, do to all of them. It's for this reason that most everyone on here who experiences snow and colder climates buys a set of "snow wheels" to swap on in the winter, because crawling over a pass and getting out to mess with chains is a pain.
Now for a quick trip like yours, I can understand why you wouldn't want that expense, so yes, chains on the frontare ok, but should avoided if at all possible.
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