Useful things to take with you
A spare inner tube; a tube repair kit; a small adjustable wrench; bicycle lock; gel seat cover; first-aid kit (scissors); small flashlight; and whistle. You should also bring or buy cycling gloves, a helmet, perhaps knee pads, and a reservoir of drinking water, preferably one of the water bags you can carry on your back.
A poncho - it may not rain but a poncho may still be useful as ground cover for the mid-day picnic and siesta. It is also useful to carry a small self-inflatable mattress for the times failure to find a hotel may mean having to camp out or spend a night in a police station - or monastery ! Also for the afternoon siesta!
A 220v immersion heater for that early morning or late night cup of tea or coffee in your hotel room.
A small Phillips travelling iron (plus adapter plug) to take the wrinkles out of your shirts and skirts before going down to dinner - no-one will guess you are travelling by bike.
A slip on towel for the beach, a tea cloth, knife (+oyster knife?), fork, spoon, and drinking glass or cup; (small bike radio).
A quick drying polyester, evening shirt and pants, two spare underwear and socks; sweater for cool evenings; lightweight wind cheater; slippers; small backpack.
Talc; salt; washing powder; sun lotion; Tylenol in the case of saddle soreness;
Maps; Berlitz; Guidebook.