I would like to do a tour (Pittsburg to Wash. DC trail) late this summer with my son. I have a KHS Hybrid (see link) that has a 28/38/48 crankset and a 11-32 cog. My question is, can I replace the 28T with a 24T or 22T and not have to make any other changes? I plan to have my LBS do the work but should I purchase the needed parts? I plan to pull a Nashbar trailer and install front panniers. I hope to stay under 55 lbs of gear. Any advice you might give will be greatly appreciated.