Here are a few links to USA tour providers. These tours can be of half day, full day or multiple day duration. Transfers can be from hotels to airports or transfers to nearby cities or resorts for a short stay. Please select the country and city of interest to you.

Tours by Tours-USA.com

Lonely Planet Tours of the USA 

Discover the USA.Com Tours

APT Luxury Touring & Cruising.com Tours

These days there are many online travel service providers rpoviding travel support and tours. These can be found quite easily via online searching.  You can reference these businesses on the Tripadvisor forums to gain prespective of the companies from TA members and to read up on any experiences that have been shared by those who have used the businesses services.