Underground transportation can be easy if you click on Subway Navigator for maps of US and international subways.

For long distance train travel in the US, visit AMTRAK.

TheTravelsite.com is too cluttered for us to recommend as an agency, but it does put all the European Rail info you could want together in one place.

If you'll be behind the wheel in the U.S., you can get free route maps, lodging and entertainment guides and discounts through membership in AAA.

Find your preferred car rental agency here:

Hertz and Alamo are best for using coupons online. The Avis coupon-redemption site can be quirky, try their toll-free number for quicker service.

Most big US car rental firms have overseas agencies, but in Europe, two of the big local names are Auto Europe (formerly Kemwell) and Europcar.