She has a Trek Silque S (full carbon/105) and we both have Trek Hardtail Mountain Bikes.

I'm pretty set on Tiagra or 105 as components, and I definitely want to ride the bikes before I buy one.

Really any of them are going to motivate me to ride with her. It's something we can do together. I ride my mountain bike with her all the time.

Looking online, I think I'm better with one of the smaller manufacturers as they tend to have better components (online Treks in the ~$1k range are Sora or Claris, same with Specialized), but I want to go in to a couple of shops anyway as the prices might be different in person.