To Northampton from Euston Station.

In November I plan to be in London for a week.  I will be taking a day trip to Northampton.  I will be staying at the Tara Copthorne which is near Kensington High Street Station.  What is the best way to get from there to Euston Station. (the railway station, not the tube stop)  Is there a tube stop that connects directly with the railway station, or do I have to go up onto the street and walk to the station?

High Street Ken. to Victoria (Circle Line) change to Victoria Line to Euston.   The escalator from the tube comes up right inside the mainline station.

Alternative - High Street Ken. to Euston Square on the Circle line and then a walk of about 200 Yards. Pretty sure it's signposted but I know it all so well I don't bother with the signs.   Anyone going to Euston Square to look in the next few days?

If you go by train in the UK, check the ticket tarriff.  The ticketing comes in many types and prices.
An open ended standard round trip ticket is twice the cost of a 1 day round trip ticket.

Check these sites

http://www.thetrainline.com/default.asp?href=http%3A%2F%2Fwww%2Egoogle%2Ecom%2Fsearch%3Fsourceid%3Dnavclient%26q%3Duk%2Brail%2Btickets&T2ID=9109_20043721475

http://www.britainexpress.com/Travel/rail/

http://tube.tfl.gov.uk/   ------  this covers the tube and busses