A 3-week business trip without checking luggage?
i would suggest packing light weight and low maintenance clothes...wash and wear pants and shirts- avoid wool pants and dress shirts that easily wrinkle. Most hotels have on-site coin operated laundry facility for guests, they usually have detergent available at front desk...use as needed to refresh your clothes.
Sports coat and winter jacket need not be packed in handcarry baggage.
Good luck with book tour!