Thanks to all of you who posted information about train travel. A big thank you to PalQ. I've looked at different fares and think I've come up with the right combination for our trip. If someone would be so kind as to let me know if I'm making a mistake before purchasing, I would be so grateful!

Intro
We are family of 5: 2 adults and 3 kids ages 9, 13, and 16. I think the 13 and 16yr old are considered youth when purchasing tickets. Our dates are not flexible. We are trying to do the following:

July 30
Eurostar Paris to London
London - Cambridge

Aug 16
London - Paris

This is what I've found out:
With Railpass $953.00

BritRail London Plus Pass $140.00
2 days in 8 days; 2nd Class
1 adult, 1 free child : 1 @ USD 70.00 each.
1 adult, 1 free child : 1 @ USD 70.00 each.

BritRail London Plus Youth Pass $63.00
2 days in 8 days; 2nd Class
Rail protection plan @ USD 10.00
1 youth : 1 @ USD 63.00 each.

From Paris to London $750.00
2 adults, 1 youth, 2 children
[11:43 AM-01:30 PM] 07/30/2006, Train 9025
Paris Nord to London Waterloo, Seat
2 adults, 1 youth, 2 children
[10:10 AM-01:59 PM] 08/16/2006, Train 9060
London Waterloo to Paris Nord, Seat

Without Rail Pass $1424.50

From London to Cambridge $148.50
2 adults, 2 youth, 1 child
[02:51 PM-03:54 PM] 07/30/2006, Train 1451
London King S Cro to Cambridge,

From Paris to London $1276.00
2 adults, 2 youth, 1 child
[11:43 AM-01:30 PM] 07/30/2006, Train 9025
Paris Nord to London Waterloo, Seat
2 adults, 2 youth, 1 child
[12:09 PM-03:59 PM] 08/16/2006, Train 9024
London Waterloo to Paris Nord, Seat
My questions are:
Are these the right passes?
Is there enough time to change stations from Waterloo to London King S Cro ?

Trying to figurew this out is driving me insane! It's kind of like those math class questions I hated. "If two trains leave the station, one heading west at 60 miles per hour to the next station 200 miles away and the other train heading east at 75 miles per hour to the station 375 miles away, which one will arrive first?"

Frankly all those figures look VERY high and I'd doubt if a railpass makes any sense

The normal return fare from London to Cambridge for 3 adults & 2 children (16 yr old is an adult)is a total of £100 ($180) & Eurostar for the same is about $450

If you buy a family railcard while in the UK the London - Cambridge price goes down to about $100

Yes, they do look very high...which is why I'm freaking out!
Those fares were quoted this afternoon by www.raileurope.com

Forget about raileurope. Buy your Eurostar tickets on eurostar.com. I can find Paris-London for your date for $638, and return for $308. Total $946.

Buy your London-Cambridge tickets directly from onerailway.com, or wait until getting to London for £70.00.

So, I found trips for your Paris-Cambridge and London-Paris trip for 5 persons for a total of <$1,100.

While the Chunnel train trip is a fun experience, have you considered flying between London and Paris? I did a quick look just on Expedia for your dates of travel between Paris and London and the flight is $157 per person. The flying time is a little over an hour plus the wait time at the airport. You may have already decided that you want to take the train just to avoid dealing with the subway commute time / security check / etc. of the airports, but I thought I would toss that idea out. Good luck and happy travels.

Just to add that the £100 I quoted for London to Cambridge is the walk-up return fare - ie what you'd buy at the station & has no limitations on when you use the outward or return portions.

As for Raileurope - my view is that it's a means of extracting as much money as possible from gullible Americans. An example is that they charges resevrations fees for all British railtravel when in reality it's free if you book via any of the UK rail companies. I've known them to charges for reservations on services that don't have reserved seats.

Anyhow best places to lok for fares are

www.eurostar.com & www.nationalrail.co.uk

To amend my earlier post, Kings Cross to Cambridge is run by www.firstcapitalconnect.co.uk. Onerail operated the slower trains from Liverpool St. But yes, you can find times and fares on nationalrail.co.uk for all.

Hi M,

>From Paris to London ...
2 adults, 1 youth, 2 children
...
London Waterloo to Paris Nord,

Without Rail Pass $1424.50<

I went to www.eurostar.com and clicked on UK.

The fare for 2cl seats for 2 adults, 1 child, 2 youth on your dates is 322GBP = about $580.

www.raileurope has your dates for $638 in 2cl and $643 in 1 cl.