I did my first tour, from Delaware to Maine, on my r300. Widest tires I could fit on mine were about 25mm, which were a bit narrow but doable. I used p-clamps to attach the rack as it had lower eyelets but none on the seatstays. I also installed a smaller inner chainring, but still didn't have ideal gearing for a lot of the hills.
After that I started touring on a steel touring specific bike, and felt a world of difference, but honestly the Cannondale tour was not bad.