Huts

All huts accepted credit cards and offer piknik packages for the day, but mostly just sweet. Even the breakfasts are mostly just sweet. 

Charging was accessible on all huts.

Most huts expects you to bring your own sleeping bag linen. Some offer renting it for around €5-6.

Half board overnight is around €50-55.

Huts are busy in the season. Booking more than month in advance might be necessary. Or you must be lucky. 

No huts have online reservation. Asking for couple of dates and then finding confirming those free in a sequence among all might be handy. 

No dogs allowed in the national park.

Transportation

It takes 3 connections to get back to the car to Valgrisenche, so you must catch the bus in Cogne around 12:35.

You must search directly on aosta.arriva.it bus operator. Aggregators like Google or Rome2rio don't have all connections.  Bus stops locations can be found also in mapy.cz, but no timetables there. 

There is no site searching all the public transport in the Italy (for the record: this observation is from 21st century and hopefully might change in the next millenia). 

In buses, credit cards are not accepted. Contrary, in the central bus station, they don't want to sell you the ticket in the bus, and force you to find a central office and return with the ticket. Better do it in advance. 

Alternatively, the taxi for around €110 can drive you back to the car. List of taxis by local tourist info.

Even more alternative way of getting to the car is to rent an e-bike in Aosta and getting back to return it before 16-17h. 

Maps

The navigation is not hard here, we used a versatile offline mapy.cz for our convenience. A paid version of Kompass map: Wanderkarte has more details.

Gran Paradiso ascent

We did not ascend the Gran Paradiso, because you'd have to carry the equpiment all the way around. Reports form ascent by Südtirol Alpin (DE), Hanibal (CZ).