I just completed NTP and Black Bear on my borrowed hybrid and am considering an upgrade to a bike that lets me shift into all the gears (a novel concept!) I'm about 5'4".
I'm certainly not looking for anything fancy, but let me know if you have a bike collecting dust you are looking to sell!
I was in NTP last year and bought a road bike. I have recently upgraded, but it's a Giant XS OCR1 road bike with Shimano 105 shifters in back and Ultegra in front. It might be the perfect size for you (I'm 5' 5"). It has a triple crank, so if you're interested in doing hilly races, it's great for that too! I'd probably sell it for $475-$500. Let me know if you're interested and I'd be happy to let you try it!
I'm still looking, so if anyone has a spare bike taking up room in their garage/storage unit/ studio apartment please let me know!
I'm not sure if you're still looking for a bike, but I'm 5'4" and I'm selling an entry-level road bike that's perfect for your needs:
It's a 2012 Trek, aluminum frame, with carbon fork and Shimano 105 components. It's gently used and is in perfect condition. I've loved this bike but just upgraded to carbon. Let me know if you want to come check it out.