Renting a car for 1-person trip around France

Alan, A car is generally not as cost effective for one person. In addition to the the rental costs, you'll have to budget for high fuel costs, tolls, parking and of course CDW, which will add to the daily rental cost. Based on some posts I've seen here recently, you may also want to budget for speeding tickets. Another point to consider is that travel by car will not be the most efficient use of your limited holiday time. If you want to just wander around the country and visit smaller towns, it's certainly an option. OTOH, if you want to see as much as possible, using high speed TGV trains (which travel at up to 300 kmH) will get you from one place to another more quickly and will reduce windshield time and allow you to see more. As the previous post indicated, the only age restriction on first and second class rail travel is for those under 26 when travelling with a Railpass. According to the rules, you must be under 26 according to your passport on the day you validate the Railpass. I'm assuming that means "26 and under"? If you're buying P-P tickets, you can choose whichever class you want. Those over 26 must travel first class only. I generally travel second class, as especially on the high speed trains that's perfectly comfortable. Happy travels!

The obvious first question is where are you going. The obvious second question is cost for just one person. Figure twenty-five bucks a day for the car, fourty miles per at eight bucks for gas, twenty for parking in major cities, and anything from nothing to a hell of a lot for road tolls. Nobody forces you to ride any class. Snow is generally workable.

Also, Alan are you comfortable with stick shift driving ? (If you can drive stick on SF hills, you should be set for anywhere!) Automatics are harder to find in Europe, and cost A LOT more. Train travel can be fast and cheap so it depends on where you want to travel. Maybe consider renting a car for parts that aren't train-friendly.

depending on when you go and where you go you want to figure out the route first. I think if you go with the cheapest stick shift and if you plan to stop at many little places, you may save money and time, but if it's just a few big cities you probably don't want a car. I used maps to navigate in the past and a 2nd person watching the road sign was really helpful, but if you plan well in advance, with a gps you will do fine. the highway is very similar to the US, and the country road is narrower but still well built. I'd suggest a car if you go to some little place in Province or Dordogne, even bus is very limited.

You don't say how long you will be in France, but if you're going to be there longer than 17 days, check into the lease-buy back options available from Renault and Peugeux. These can be less expensive than renting, and have the advantage of including all insurance and you get the car you want, not what is available at the time you pick it up. Also, diesels get better mileage and the fuel (gazoil) is a little cheaper than regular gasoline. The price for regular gas in Paris right now is 1.85 euros per liter. Three years ago I paid 1.10 euros for gazoil. If you want to spend a lot of time in the countryside, a car will work better than the train, but if you want to spend most of your time in cities, then the train would probably be a better option. Driving in France isn't difficult, but driving in cities and large towns can be a challenge and parking is expensive and hard to find. Bon voyage.

As others have said it depends a lot on where you want to go and how long you plan to travel. Last summer I traveled solo around France for a month. I had orininally planned to lease a car but my final itinerary ended up being a combination of rental cars and taking trains so that wasn't feasible for me. I purchased most of my train tickets ahead of time and they were cheap. I rented a car for Provence and then again in Normandy and Brittany. Certain areas of France (and almost any country) are better explored by car so a lot depends again on where you want to go. An adult rail pass is the only time you're forced into 1st class. At 26 you should still be able to get a youth 2nd class pass, but don't get a rail pass w/o comparing costs with 2nd class point to point tickets which are almost always a better value. Car rental or lease can be a bit pricey for one person alone, which was one reason I did some of my route by train. I drove a lot on non-toll roads so that wasn't too much of an issue (just kept lots of Euro coins in a plastic bag in the glove compartment). Fuel cost was quite high even for an economy car using deisel (gazoil) which last year was running between 1.45-1.59 euro/litre or a bit over $7/gal.
And yes, a person alone can manage to drive around France w/o a navigator (or a GPS) as long as you have good detailed maps and are good at reading them and you aren't afraid of getting lost once in a while.

I'll be traveling France for some time by myself How long is the whole trip, Alan? Are you aware of the Schengen restrictions?

Beside all the practical points already raised - you would probably meet more people traveling by train and it would be less lonely - for a young guy it may be more fun by train and you would run into more kids and get invited to stuff. Usually always hotels, restaurants and bars around the train stations. Unless that's not a consideration.

Depending on where you are going, it is probably a good idea to do a bit of both. The trains will probably be cheaper, and will free you from the burden of having a car in cities. On the other hand to really get to know a region you'll want a car. Some regions are poorly served by rail. Of course it is very much a matter of personal preference, and if you'd prefer to go 100% car you should. But the trains can be very helpful and pleasant, even fun. And you can rent serially, one rental for Burgundy and another for the Dordogne (say). By the way, your first question makes me wonder if you are assuming you will use a rail pass on the train. You can, but changes on the pass system have made them generally not as good a deal as they once were (though one might be right for you anyway). Point-to-point tickets can be very reasonable if purchased in advance.

Although you didn't specifically ask, the question comes up all the time whether rail passes are more economical than buying point-to-point tickets. The standard answer is to price the point-to-point purchases first. At 26, you do have an advantage sometimes. Remember that many long-distance trains offer cheap tickets well in advance with the price gradually rising as the day of travel nears. Also,some long-distance trains require seat reservations which must be purchased separate from a pass, meaning more hassle and more charges. Third, France no longer participates in some of the passes.
Having your own wheels lets you explore places with no public transit. Whipping across the countryside in the amazing high-speed trains is both comfortable and less complicated. Maybe you could try some of both?