Paris Museums and others?

As kindly as I can, I suggest you buy a good guide book for Paris. Read about all the museums and decide which ones are of interest to you. As for "what else is there?" you will find that in a guide book, too. As for a car in Paris, not a good idea. Parking is difficult and expensive.

A car is just a problem in Paris, do not get one. Parking is very expensive and very difficult to find near any tourist sites,, it will be nothing but trouble. If you wish to have a car for other parts of your trip then park it outside Paris in a long term parking lot and take the RER into Paris.

I agree with Norma and Pam. Unfortunately with only 2000 or fewer characters per post on this helpline, and with most good guidebooks running around 300 or more pages it will not be possible for us here to duplicate what you can get from a guidebook - guidebooks have all the answers to your questions. Can I suggest you get one or more good guidebooks about Paris, and when you have read and digested them and have specific questions then return and we can help you. Unless you have previously located a place to park any car I suggest you not consider arriving in Paris and then trying to find parking, especially as this appears to be your first trip to Paris. Also, I note that while your question is about museums and sightseeing your question has been posted to the "Transportation" section.

You ask how easy is driving with GPS?. Is this to be your first use of a GPS or do you have one at home? If you already have one it will work much the same in France.