I'm taking my family to DL tomorrow (left it a bit late I know) and have just read a post saying that you can get the TGV from CDG to DL. We are staying in Bussy St Georges, a couple of stops from DL so presumably we can get the TGV to DL and then the RER from there. My question is, what is the difference between TGV and RER, other than speed, is TGV very expensive?

I've tried looking up prices online but have found it very confusing.

Keeping my fingers crossed that someone sees this before we go.

many thanks

Louise