Monaco to Paris on Monday June 1st to catch 5pm flight from CDG to JFK
 

I did a bit of research on TGV and flights. (Unfortunately, can't change CDG to JFK.)

running into a problem to get from Monaco to Nice TGV to catch the 7:04 am train to Paris

The earliest bus from Monaco (the 100) won't get us to Nice in time.

Hiring a car appears to be 80Euro to catch the train, might as well fly Nice to Paris in that case. As the backup plan appears to be to take a bus to Nice and then fly from Nice to Paris.

If anyone has any experience, or other options, they would certainly be appreciated.

Go the day before

I agree with Gretchen.

We flew from Nice to Paris Orly.

Schedules for Nice to CDG, non stop with prices on Skyscanner.net.

No way would I chance this - train strikes happen all too frequently in France. While they do announce them in advance and some trains will continue to run -- it sure isn't worth the angst.

Go the day before; by train or fly.

Why don't you just fly, what reason do you have that you don't want to? Nice airport is fairly small and not that problematic to deal with. And you want to leave from CDG, anyway, so there isn't any issue to deal with in getting from CDG into the city. Why do you want to take the train and spend a whole day doing that, vs. an 1.5 hour flight? I suppose the TGV will be bit cheaper if you buy second class (not much at this date that I can see), but not much at all.

Hop, a subsidiary of Air France has 3 flights leaving Nice between 9:30 and 13:05 going to CDG. The 13:05 flight gets there at 14:40. If you want to be safer, the 10:35 flight gets there at 12:10 (145 euro). Easyjet has a flight at 9:05 for only 90 euro. Add on 10-20 euro to check a bag.

I don't even see a TGV from Nice to CDG at 7 am on 6/1, though, are you sure? The only one I see is at 9:05 and doesn't get there until 4 pm, too late. The only possible one leaves at 5:53 am and isn't direct, but does get there in time (1:02 pm). I guess you are going into Paris, not CDG, which means then you are going to have to get from PAris to CDG, what a hassle when you can just fly there.

Just fly from Nice to CDG. There is a shuttle every 30 minutes or so.