paris, loire and brittany site advice

We are travelling in early May hoping to stay on a site for a week with easy access to Paris and maybe a walk into a town, then we are going to the Loire so would also like a site  within walking/cycling distance to a town and access to the Loire a velo cycle route, then we would like a site near the coast, Brittany perhaps?   We have camping cheques and an ACSI card. Has anyone used the train to transport their cycles on the cycle route? we have four weeks and would welcome any suggestions.