Try the Hotel Colbert, and ask for a room looking out at the towers of Notre Dame. Or try the Hotel d'Angleterre, and request a view of the quiet courtyard. You could also settle into one of the hotels on the Ile St.-Louis with a glimpse of the Seine, or at the Hotel Jeu de Paume on the inner courtyard - and avoid rooms on the noisy Rue St. Louis. Rooms in these moderately priced hotels (by Paris standards) have attached baths.
Serendipity may take care of your meals as you walk around. My wife and I stumbled upon the parasol-shaded L'Ebouillante on the Rue des Barres, a pedestrian way sloping gently from the river opposite Ile St. Louis to the Marais district. We returned there for the pleasure of eating a lazy, tasty, light meal while watching Parisians go about their daily routines.
I'd skip dining in the pricey Champs-Elysees district unless you're going to a highly recommended one- or two-star restaurant. In general, food is sharply more expensive in Paris than in the provinces.
Incidentally, if you wish to order a glass of tap water - perfectly tasty - with a meal, just ask for ``une carafe de l'eau.''
Getting out of town:
You can pick up a rental car at the Air France bus terminal on the Esplanade des Invalides. Ask the agent how to get to the Peripherique (Paris's ring road) and one of the high-speed ``A'' toll roads that get you to the point where you can wander off on charming rural roads.