Looking at options for getting to our apartment in the 7th from terminal 2g, 2 people, midday on a Tuesday in December. We travel with a roll-a-board and daypack and can negotiate stairs and crowded public transit which we tend to prefer but it gets old real fast when repetitive in one trip.
First, flat rate shuttle from apartment service pricey ($65), but easy - walk out one door and in another.
Then RER - get shuttle N1 at terminal2g to another terminal where you catch the shuttle to train station. Navigate train station to RER B, get loaded with luggage, ride to St Michel, navigate St Michel (up/down/across?) to RER C, get loaded with luggage ride to Pont d l'alma, navigate to surface, walk about 1/2k.. Cost 22.90 euro or about half the shuttle say $15 more to go with the sh ption of opting out for a taxi at St Michel (there is a cab stand in the vicinity I assume) to eliminate a transfer and short walk for about 8 euro. Cost - 27.50 euro.
Roissy Bus - get shuttle N1 at terminal 2g to another terminal with Roissy pickup. (I don't think Roissy has a pickup at 2g could I get that confirmed?) Get on Roissy bus, luggage underneath, get off at Opera, navigate metro station, load on line 8 with luggage, ride to La Tour-Maubourg, navigate to surface, short walk. Cost very similar to RER above, also with taxi option presuming a taxi stand in the Opera vicinity.
Since we don't have any place to be at a specific time I'm leaning to Roissy / taxi as having fewer, easier transfers than RER the main advantage of which seems to be it doesn't get held up in traffic. Although it is tempting to pop the $30 for a door-to-door.
I'd appreciate thoughts of those with experience and especially confirmation of assumptions