Cherbourg is easily accessible from Normandy and the rest of France and is around 4 h from [wiki=e20d37a5d7fcc4c35be6fc18a8e71bfa]Paris[/wiki] and around 7 h from [wiki=a6f0077b898dc8d408c08168a2c44259]Bordeaux[/wiki]. There is not much traffic except during rush hours. There is limited parking close to the old town and you may have to pay for it during the day.
Cherbourg can be reached from Paris St Lazare on a direct train, otherwise there are services to Brittany and to (sometimes) the southwest of France. Gare de Cherbourg is about 5 minutes' walk from the old town. It is also close to some hotels and a Carrefour but it is difficult to find food near the station.
[url=http://www.brittany-ferries.co.uk/]Brittany Ferries[/url] operates a regular cross-channel service from [wiki=a52a2b4f2219a19dd23d1593548cb478]Poole[/wiki] that takes about 5 hours. Frequency varies depending on the time of year.