Offer her a piggy-back across

This seems like a perfect opportunity to act like a gentleman, and doubles as a nice excuse for some physical contact.

"May I carry you across this obstacle, Olivia?" you ask, perhaps a little too cheesily.

However Olivia happily agrees. Not because she wasn't more than able to cross herself, because the stream was very shallow indeed, but maybe she likes her legs around your waist...

Laughing she hops up easily enough, you wonder if it feels nice for her pushing up against you like this, feeling the muscles of your hips and waist move between her thighs. Unfortunately the stream doesn't take long to cross, but on the other side you easily go back to walking hand in hand. You're already looking forward to the trip back across the stream.

It's starting to get hot now, and you really feel like taking some clothes off.