Robert Forward's "Rocheworld" does the best job I've ever seen at thinking up a plausible scenario for travel to a nearby star, plus a fair attempt to weave a human plot into the timescales involved. Also excellent was Forward's "Dragon's Egg", while other books by him are not nearly so good, specifically the sequels to both of these.

Both Sanford's "Genetic Entropy" and Behe's "The Edge of Evolution" contain back-of-the-envelope order-of-magnitude musings on "scale" related to the random-mutation-fantasy. David Swift's "Evolution Under the Microscope" stands out for repeatedly marveling over the "folding" issue, including the snip-and-rejoin magic needed to copy a helix. I mean I have repeatedly had the experience of spending tens of minutes unraveling a 50-meter stretch of 11-millimeter Edelrid perlon climbing rope, which is specifically designed to be easy-to-handle. The idea of your genome getting tied up into knots, I mean really you DO want to ask how it possibly AVOIDS getting tied up in knots !