Don't go on a Marathon Trip... 8+ hours to a guy is awesome... 1-2hours for a girl is ok...(and pushing the limit, especially if not catching)
Take her Panfish fishing ( Quantity over Quality) Keep her interested
buy her a rod/reel/tackle bag - Pink in Color for all 3...
load tackle bag up with bright lures (pinks, neon Yellows, any colors you wouldn't get, etc...)
the reel a spincast would be easiest for her... a spinning reels is nice, but it'll take her a while to learn to cast (when to release the line)don't even think about a baitcaster
Last but not least...
Careful what you wish for... if she really gets into it, you'll have no more "alone time"