best transport

Unfortunately you really need to define easiest and quickest because they do not always go together. Since you are at the airport than a flight (if it exists) to Rouen would be the easiest and quickest. A ferry is the least quickest. Buses and trains in between. And if you are headed to Rouen why land in London and not Paris? That probably would be smarter.

Since you will already be at Heathrow, the quickest probably will be to fly to CDG, go into Paris, and take a train to Rouen. Take the RER B from CDG to Gare du Nord and transfer to the RER E at Magenta (attached to Gare du Nord). Take the RER E to Haussmann - Saint-Lazare. Take a SNCF (French National Rail) train directly from Gare Saint-Lazare to Rouen. What time is your flight scheduled to arrive at LHR?

Yep. Not sure why you didn't fly to Paris. It's like someone from Europe who flies to Cuba to go to Ft Lauderdale, FL. I guess since you decided to fly to London, one option could be to look for a flight to Paris, then take the train from Paris to Rouen. Of course unlike Cuba and Florida there is also the Eurostar train option under the channel. You can take a Eurostar from St Pancras station in London to Paris Gare du Nord. From there transfer to the St Lazare station, still in Paris, via bus, metro or taxi and from St Lazare take the train to Rouen. About 6 hours ride from the London St Pancras station altogether.

HI guys, thanks for all your input. We did not fly into Paris because we purchased airfare at $501 to land in London instead of $2500+. We believe it is because of the Bourget airshow......sigh. Anyhow, my husband is Parisian, we have an apt there and are going for work mid June, but are staying in Normandy 2 weeks prior. We were really just interested in others' experiences in getting across the Channel....