Great, great film and easily Ford's best work.
You never really think of Harrison Ford as the actor you would re-watch a film for just to see his performance, but here it is true. And I can't speak for the book but I wholly agree that making Allie sympathetic was a necessary choice. I can't imagine how the story would work if the initial lure of what they(well, Allie really) were after didn't translate, to some degree at least, to the audience.
And "...double-digit inflation and a two-dollar loaf of bread!" has entered my personal lexicon as the go-to quip when getting interrupted by a loud noise.