I've a nit to pick: On page 156 Will receives a new bicycle, one with "eleven gear-speeds". I don't want to go into a great deal of detail why, but I don't think so. A typical freewheel was five gears, so double chainrings would give you ten "speeds", and a triple would give you fifteen. Not necessarily all useful, of course.
Good writing, wacky plot, enjoyed the trip rather much.
Some docks were occupied by sleepy argosies... (pg. 248) -- A merchant ship.
...located at the rear of the texas (pg. 261) -- The uppermost deck of an inland or western river steamer. But this is an ocean steamer!
...Galaxy is the length of a football field (pg.8) -- Well, it's sixty feet short of a football field.
Roman Inquisition (pg. 31) -- Not interesting.
sided in titanium (pg. 137) -- Who'd a thunk it? This led to discovering the phrase "titanium chic".
an eight-by-eleven gray envelope (pg. 181) -- Guess my 8 1/2 x 11 paper won't fit in that.
...twenty-foot Mako...on a jack stand (pg. 378) -- A feat of balance!