What is the best way of arranging a student tour of Washington DC?

I am a teacher who is contemplating a seven day trip to Washington, DC etc. in the spring of 2007 for my seventh graders. There might be 2-3 buses. Several companies have contacted me with great offers and personal incentives (stipends. travel benefits, and bonuses) to compensate for the amount of time to set up this trip. Is there anyone who has some good referrals, advice, or suggestions?

Contact the Youth Hotal on K and 11th Strreet in DC. for your rooms and the other info you need.

School Trip Group Hotel – Teachers, Students Travel Lodging

Tours to Loches $12 Travel from Tours to Loches by train

Tours to Morlaix $59 Travel from Tours to Morlaix by train

Tours to Chantilly $42 Travel from Tours to Chantilly by train

Tours to Beaune $66 Travel from Tours to Beaune by train

Tours to Monaco $150 Travel from Tours to Monaco by train