Derek Low explains how to do a cross-country train trip for just $213. You don't get a lot of time to sight-see off the train, but this still sounds like quite an adventure for a pretty affordable price (one way). The entire trip takes about 4 days.

How much did it cost me?
I paid $429 for a 15-day rail pass. You can do it for much less.

The rail pass includes 8 train rides which I used to explore other cities after my cross-country journey. If you’re thinking of stopping at a few cities, a rail pass can be a great value. Note that a 3-day journey counts as one ride, but so does a 30-minute one! If you work out the math, each ride is $54 on the rail pass. In comparison, most long-distance journeys cost upwards of $80.

For some people, buying the direct California Zephyr and Lake Shore Limited tickets should suffice in getting you from San Francisco to New York. Tickets for the entire journey are available from just $213.