If I were you I would break the schools into the following 3 groups based on their geographic locations
1)Tuck , Cornell , Wharton and Yale
2)Darden, Duke and Kenan-Flagler
3)Ross and Kellogg
You can start at New Hampshire(Tuck), the go to Connecticut, then to New York and finally to Wharton in Penn.
I think you shud land in New Hampshire or Vermont and may be drive through this whole route. Let's say youe take one day to visit each school. You can finish this area in 4-5 days. Visit school in morning and drive in the evening/nights.
From Penn you could go to Darden in Virginia(by air may be). Then Raleigh/Durham in North Carolina is right next door, you can drive.
Then you could take a flight to Chicago. Chicago to Ann Arbor(Ross) you can take a bus. This is what I did when I visited these schools. Then you can think of taking a flight back home from Detroit.
You can also enter first in Chicago and then take the exact reverse of the above. One advantage of this is that you can plan your NY visit last and then fly back home from there. NY having 2 big airports you can get better flight deals I guess.
If you do plan on driving around in the group-1 area then u shud probably put it to the last of the 2 weeks because then your jet-lag might not be bad enough to trouble you during your drives.
Ideal time to visit schools - After September and before December.
Best = Sep- Oct
Here are my reasons:
1 - Classes start in early fall and hence class visits are available. Summer , weather wise , is probably the best time to visit schools, but you might miss the opportunity of 'experiencing' the school community since most of it is out in internships or career trekking.
2 - You will get a chance to meet new students who you can relate more closely in terms of applying to schools etc. Also second year students would have just been back from internships and will have a lot more to say about the B-School experience.
3 - Winter(November-Dec) is probably not the best time.Apart from the weather, think about the busy recruitment season going on on campuses.
Hope this helps.
Wish you all the very best in next year