The seaside is really close to...
The seaside is really close to Nantes (40 miles west) and there is the nicest beach in Europe : La Baule.
It's a 15km long beach with a nice sand!!
Once there, you should also see the 'Wild Coast' from Le Pouliguen to Le Croisic...the landscape is wonderful!
Nantes & the Loire Valley
Nantes was a charming city on the Atlantic coast. I found the city to be accessible, friendly, and have great shopping. I loved the architecture. On the outlet of the Loire River, the city is a perfect starting or ending point for exploration of the Loire Valley. I can speak basic French, and I would highly recommend you learn to do so as well before you go. Here in the city, most speak English, but are rightly offended if you don't even try to start in French. I found that even if I made the attempt and stumbled, they would help me out, and were kind about it. So much for the rude stereotype: but I can relate. I'm a New Yorker! As a warning, the men were VERY forward- I was a woman travelling alone, and not only did I get picked up several times, they were very physical and difficult to get rid of.
The city (town?) of Sancerre was both breathtakingly beautiful and a wine-lover's dream. The trip out required a car, but it was well worth it. The surrounding landscape has dozens of microclimates perfect for a variety of grape growing for winemaking. The town is absolutely adorable, and easily explored completely on foot, once you get there. The views of the surrounding valley are stunning.
"The Loire Valley"
As for the valley itself, the gardens and chateaus are a must: and I enjoyed the ones that weren't necessarily the most popular. While Chenonceau and Chambord are easily the most recognizable, I found Loches and Montresor the most inspiring. Loches was like walking right back into a medieval city: I happened there on market day, and it was bustling with activity. Montresor was filled with antiques and art. The gardens at Villandry were unforgettable. The food is good especially when you don't get too fancy and follow the locals. Always drink the wine. I found the smaller towns and bed & breakfasts were generally better than the larger cities and chain hotels for my tastes. I adored Amboise, but Blois felt seedy shortly after the sun went down.