Some ideas for you, depending on how much time you have. Forward this to your sweetie.
One hour
Make the most of it; come up with something thoughtful. A list of reasons why you love her paired with her favorite wine. Her favorite dessert with a framed photo of the two of you. Something handwritten she can keep.
Night at home
Make a roaring fire, clean the house, put on nice music, make her dinner. Let her relax with a glass of wine while you are cooking.
Night on the town
Thoughtfully plan a pairing for the evening. Maybe drinks at a cozy bar and then dinner around the corner. Maybe dinner and then some live music. Maybe a picnic and then a nap. Maybe a walk and then a movie. Maybe an afternoon hike and then a happy hour. Please find things that are close together so we are not spending the evening in the car.
24 hours
Book a room at a nice hotel in your own city. No need for traffic or airports. Grab her makeup, toiletries, brush, change of clothes (if you trust yourself, if not give her 10 minutes to pack). If you are lucky to live somewhere warm, take her to the hotel pool for the afternoon.
Weekend
Find somewhere about 1-2 hours away from where you live. Enough so that you feel like you're getting away, but not so far that the weekend is spent driving. Find a few things to do in this place and give her the options. She may be really into the historical museum, or she may just want to spend Saturday in bed!