Wow!! You're amazing

I don't know much about the Jamis bikes, but 2 of mine would do what you're looking for. I have a Trek 520 (touring) and a Surly Cross Check. Both are steel, and both can be built with pretty low gearing. I rode the Cross Check in the MS 150 last year with skinny tires, and have ridden lots of gravel with wider tires on it. The Trek 520 went over lots of gravel (road construction) with me yesterday. The 520 has a lower bottom bracket and is longer (better for rear panniers) - the Surly is more nimble.

Our LBS manager has a 20+ mile each way bike commute. He rides an Aurora with cross tires. He LOVES it (completely de-constructs and frame savers every 6 months). He says he plans to keep it forever - I believe him!!

Good luck!!