Nice to chamonix drive

borivlikar,
I usually use viamichelin.com to get an idea of drive time. The site is pretty easy to use, and sometimes offers more than one route (e.g. cheapest, fastest, most scenic). It also gives an idea of costs (e.g. tolls). It underestimates the time, IMO, because it doesn't allow for gas/food/comfort stops, so we always add time to theirs....1-3 hours, depending on distance. It will give you an idea of time, however. As you have mentioned, mountain driving will be more difficult than the regular autoroute. Viamichelin.com is a good starting point.

Where to break the journey, I couldn't say. Always observe the speed limits. If caught on a camera you may get a ticket a few months after returning home, plus a fee from the car rental company (to reimburse them for giving your name, etc. to the traffic agency concerned). If you get one, pay it asap as the price goes up fairly rapidly with a delay. Re insurance, we never used to buy the CDW from the rental company, relying on our credit card, but nowadays we buy the insurance for peace of mind and ease of claims should we have an accident (So far so good! Knock on wood!) Insurance costs I don't know. It seems to me when we last rented a car in France, in 2023, we paid less than we expected to. As in the states, take photos of the car in case there are any dings already there.

Note which kind of gas your car takes and learn to recognize the pumps (gasoline or diesel). Have a tap and pay credit card (or debit card) to use for tolls if need be. Get an International Driving Permit (not license!) at AAA (about $20.00, photo needed too) and keep on you, just in case you are stopped for anything. Your state driving license should be current.

Wherever you plan on staying, try to figure out your parking before you arrive there, unless your lodgings have parking on site. Some towns are a pain for parking; others have public lots that are easy to find and access. Better to know ahead of time so you don't spend an hour looking for a place to park when you arrive in a place. In some towns/cities parking is expensive.

Glad you are renting and returning in France. There are big fees to drop in a different country (500-1,000 euros). Be aware of any special stickers/permits needed (like the ZTLs in Italy).

This is probably WAY more info than you wanted, but I hope I have been of somer help. Bonne chance et bon voyage!

You don't say when you plan to drive, but, if by chance you plan to drive during
the last weekend of July, all bets are off, as this is usually the worst weekend for
traffic in France. The half of the country that took July off is going home and the
half of the country taking August off is heading out.

I assume you are allowed to drive the car in Switzerland? If not, your drive time
will increase to be able to stay in France when approaching Geneva. If you do
drive in Switzerland, you will either need to avoid the toll roads or purchase a
vignette (or make sure the rental car has one already).

The drive into Chamonix coming to/from Geneva is almost all highway, assuming
you can drive in Switzerland, so you should have no issues there.

Adding to Judy's comment, in Europe, diesel and regular fuel pump colors are
often reversed from the US (diesel is black and regular is green). Obviously
you don't want to get it wrong.

These days, at least in my experience, rental cars have technology that displays
the speed limit very accurately. As long as you pay attention to your car (!) you
should be fine for speed limit.

First, are you sure you can't take your rental car via Italy? In my experience, there was a hefty charge to drop off a rental car in another country, but I've often driven through other countries (rented from Germany, drove to Switzerland, dropped back off in Germany; rented in Switzerland, drove through Liechtenstein and Austria, dropped off back in Switzerland). Maybe I was breaking rules I was unaware of? Check to make sure because Italy is easily the fastest route.

If you have to stay in France, Nice to Chamonix is multi-lane autoroute (aka freeway) almost the whole way. A8 to Aix, A7 to Valence, various autoroutes through Grenoble to Albertville. From Albertville to Chamonix is D roads, but almost all multi-lane. This means (a) on the autoroutes, France has these wonderful aires (rest stops) with gas, food, toilets, etc. You don't really have to plan them, they just show up every half hour or so; and (b) on the D roads, you will be passing through several towns where you will pass by many gas stations and cafes for rest breaks; and (c) these aren't high, twisty mountain roads; these are road through the valley bottoms. Looks like 6.5 hours. Myself I've only done the part from Chamonix to Avignon, in the other direction. Its a nice drive. The most scenic part for us was Lac Annecy but that is on a slightly longer route north through Annecy and Chambery.

As for insurance, check with your credit card company. My card comes with rental car insurance (as long as you use the card to pay for the rental), and I decline all insurance offered by the rental car company.

Bon voyage!

Italy is probably the fastest route with the potential exception of the queue to go thru
the Mont Blanc tunnel. Also note the cost of the toll to go through the tunnel if you
think about that route (56 euros, if I am looking at it right).

I think the website or app will give you real-time status of the queue to come thru the
tunnel from the south. At Aosta, you kind of have to commit, or it's a bit of a backtrack
to come into Chamonix via Martigny.

I seem to recall reading that Mont Blanc tunnel will be closed for maintenance later this year. Depending on when you are driving to Chamonix, if you do happen to pass through Italy, check the tunnel closure status: https://tunnelmb.net/en-US/closures-and-forecasts

I am using Amex Premium Car rental protection for car rental insurance. it covers CDW and theft protection for a flat rate per rental. Third party liability is offered as part of car rental in Europe. Your US car insurance likely will not cover car rental overseas. Any fees (such as one way, premium location charges etc) will be listed in rental terms of conditions when you book the car. You can search the rental company website ahead of time and go over it.