Try entering your flights/dates on ITA and see what results you get. Use the multi-city function and you after you enter your first two flights, click to add a flight. If you want to search a particular airline/alliance, use the advanced routing codes tab (enter this way: / alliance skyteam ).

http://matrix.itasoftware.com/

My advice: Click on your own screen name and find your previous thread. Continue there. And notify the moderator to delete this thread.

Shortly before midnight on Tuesday Sept. 3 the Amtrak Cardinal #50 will be leaving Indianapolis through West Virginia to Washington DC. It arrives in Washington about 6 PM Eastern the next day. The fare is less than $100 which may be a bargain compared to airfare. My past experience which may no longer be valid, is that flights from BWI are a bit cheaper than from Philadelphia or National. Both BWI and Newark have Amtrak stations attached to them either by shuttle bus or monorail.
http://www.amtrak.com/home Buy your Amtrak tickets online at least 2 weeks before your trip. The price usually goes up, sometimes twice within the last 2 weeks.
You can also get from Penn station in NYC to the Newark airport train station on NJ Transit for less than the Amtrak fare.

Can't we go back to this thread from the OP in Oct instead?

http://www.fodors.com/community/air-travel/how-to-do-a-multiple-city-trip.cfm

Buy your train tickets as soon as your dates are set. The prices go up as the seats are sold. The prices for sleepers especially go up fast, and sleepers sell out.

Thurs: I won't need a sleeper as both of the train trips are less than 4 hours each.

rkkwan: My advice: Mind your own business. The information in the first post didn't help and my travel plans have since changed slightly. Therefore, I am seeking new information that will better guide me.

Hey Tom, sorry I missed your post. I'm actually flying from Indianapolis to New York, taking a train from New York to Philadelphia, train from Philadelphia to Washington DC and flying from DC back to Seattle. I've done some research and can make the whole trip for $643.00 or less if I choose different flights/trains. The ones I was looking into right now are the following..

Seattle to Indianapolis (United) $209.00
Indianpolis to New York City (American) #183.00
New York City to Philadelphia (Amtrak) $36.00
Philadelphia to Washington DC (Amtrak) $35.00
Washington DC to Seattle (Alaska Airlines) $180.00
Total if I go this way: $643.00

I can get it as cheap as $557.00 if I choose to fly super early or really late.

Incredible how the longer the flight, the cheaper the ticket was. I haven't purchased those tickets yet but with the service I have, those prices are locked in until the end of the month.

If you wanted to leave Indianapolis at 6AM on the train to Chicago, you could get to either NYP, PHL or WAS for less than $155. Don't forget you will have to pay for transportation from the New York airport of your choice into Manhattan. NYP is right in the heart of NYC and the subway is right underneath.
You also save the cost of a hotel room for a night in NYC.
You would also have the chance to see Chicago for a few hours in between trains.

Hey Tom, we'd be flying into LaGuardia and the hotels we looked into all have free airport ---> hotel transportation. I will look into Amtrak between Indy and NYC again though here in a few minutes. I have a discount card for Amtrak as well. I'll get back to you with my results. Thanks!

It appears to be a 21 hour trip on Amtrak. Longer than I was interested in spending on the train. Would rather pay extra to fly.

Thought you might be interested in a couple hours in Chicago. I do understand not wanting to spend over 20 hours to get to New York.

Great! Just want to let everybody know I helped the OP in the previous thread. This is what I got in return. You're very welcomed.

I agree rkkwan. Very rude comments by a new poster. After reading the previous thread I see you gave the OP a lot of very good advice (and on some of his other threads).