Watching Indiana Jones right now, and Marians comments like "I was just a child" and Jones' falling out with her father seem to indicate that Jones fondled a child in the story. Which... uh. What the hell? It's not even like a big part of the plot, it's just thrown in
I guess he looks older, but she doesn't look 22 or anything. An undercurrent of their relationship is that she wants to have kids someday and is feeling out whether he wants them too, and it's not certain that their relationship can last into the long term if he doesn't.
Dern was 26, Neil was 46 during filming.
Sam Neill has always looked mid 50s. I assume it's cuz of too much Aussie sun (only half joking).