A Cross Check is a blank slate, do whatever mods you want and it will probably work out all right.
Take a look at your crankset and see if it has the threaded holes for an inner ring. It might... the same crank was on the LHT and Surly are thoughtful about things like that. The catalog also says it has a triple front derailleur even though it's a double bike... that might be a typo. But if all this holds true, buy the appropriate 74 bcd x 26t cog and five chain ring bolts, and you are nearly all set. But if it doesn't hold true then a triple crank and FD will swap right in.
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Genesis 49:16-17