Reamde would have been my first recomendation to introduce someone to Stevenson. Constant action, an unusually direct storyline for him, and not too too much time spent off in the weeds.

Of course some might argue those are the best things about his books, but while Chryptonomicon is perhaps my favorite sci-fi novel I've read, I think it takes a certaim type of person to enjoy a book where the plot gets interupted for 5 page descriptions on how to eat Captain Crunch or a who fucked who of the Greek pantheon.