Road trip,
I would test ride a few bike. REI has several steel framed bikes. The Raleigh Clubman
http://www.rei.com/product/796450 is close to what a Surly Pacer will ride like.
Also ride an aluminum bike in the same price range. The Aluminum bike will be stiffer. However you will increase the amount of road buzz that you will feel in the seat and hands with a lower cost aluminum bike.
I went with steel when purchasing a road bike two years ago. I was able to lose weight quickly, mostly because I enjoyed the ride of the bike. I rode 5000 miles my first year on a road bike, and the ride quality of the steel frame made those miles enjoyable.
Michael