I did a long tour on a racer. I drilled holes into the bottom triangle to accomodate the rack-this probably was not a great idea. I had a slight problem with heel clearance on the panniers. My derailleur
could only accomodate a 24 tooth cog max. For full loaded touring I would not recommend it; light credit-card motel touring would be no problem. If you want to carry weight and do camping, I would suggest a light rack and pannier system on the back, and get a BOB trailer for the majority of the load.