Extremely hard film question

All I can remember was that there was a woman who I think pretended to be a man for some reason and these men find out. I think it was set in a jungle or Island?? I don't know and they lived in a treehouse or wooden cabin. Its an old movie and I think its American or British. 

One particular scene I remember is when the man and women were walking in the jungle (I think) and the women struggled to get across the river or something. When the men found out she was a women they were very chivalrous, but before they thought she was a weak man.

I can't think of any more details and I honestly wonder if it was a fever dream at this point. Haha