lots of choices out there... and you won't go wrong any way
Ciao Caroline and welcome to our Forum!
Congratulations on the upcoming wedding! And how wonderful you've chosen Italy for your honeymoon - it will be beautiful, romantic and very memorable
Four days isn't a lot but with a car you will definitely be able to fit quite a bit in.... Florence on one day, then some wine tastings, maybe a half day cooking class and sightseeing around the region the rest of the days!
Basing yourself in Chianti is a very good choice - and practically anywhere you'll be, you'll have vineyards and olive groves around. Most of the accommodations you'll find ARE surrounded by the countryside, whether they call themselves villas, farmhouses, hotels or B&Bs. What you have to look at is their description of their immediate surroundings and their general location to find the right place.
You will find many that offer less than a week's rental but it will depend on your dates! And each one sets its own policies and calendar, so you'll have to contact the ones you like and just ask. For example, Easter in 2012 will fall on April 8 and April 9 is a holiday here as well. Then April 25 is National Liberation day so another holiday. Many places will allow just day stays around those holidays, usually at a slightly higher per day cost. Not knowing your specific dates I am just giving you this general info.
Here are some I think would be perfect for you which you should look at and contact for availability and cost. These all have links to the official sites, but the pages give a good summary so that you can narrow them down.
Il Cellese in Castellina in Chianti - a farmhouse with apartments
Tenuta Quadrifoglio - more of an estate with several restored villas divided into apartments but also with just rooms - those are definitely available for shorter stays that a week.
Palazzo Malaspina B&B - a very romantic place in a Renaissance palace in the center of San Donato in Poggio, a small medieval village in Chianti. So you're not in the immediate countryside but the whole small town is surrounded by vineyards. We had wine tastings and tours in a nearby winery just outside of town, I'll have to look to see if I can find the name to give you, we really enjoyed it.
Il Poggetto - a family run residence in a farmhouse near Montespertoli
Borgo della Meliana - more fancy and elegant, they call themselves a resort... they do have several pools and beautiful views of the countryside with vineyards all around
Cabbiavoli - accommodation in apartments around a restored villa/castle - definitely very nice (Julia Robert's vacationed there a few years ago - in the villa, of course
)
Casolare di Libbiano - a family run B&B near San Gimignano. They offer cooking classes directly too.
Viticcio Wine Estate and Farmhouse - a wine estate in Chianti also offering accommodation, so this would be staying directly at a winery. Greve is also very central to visit the whole area and seeing "chianti"!
Romitorio di Serelle - near Castellina in Chianti, offers apartments in another area surrounded by wineries
All these are in Chianti and as such there are wineries and vineyards all around. Some offer rooms, others apartments. Keep in mind that even if you stay at a place that doesn't have their own production of wine (most do, though), you'll have options for visits, tastings and classes nearby. When you contact these places, you can always ask them for info on their immediate area. They are usually the most well informed of services they can offer their guests by them or their own neighbors!
Please don't hesitate to ask any other questions you might have
Hope you're enjoying planning the trip - in addition to the wedding - at this time, we know it can be stressful, especially since there are so many choices!