I will leave out all suggestions about the route you should take, knowing that your information, gained daily in the course of events, will be better than any that can be obtained now.
It may not be possible for you to march to the rear of Petersburg; but, failing in this, you could strike either of the sea-coast ports in North Carolina held by us.

From there you could take shipping.

It would be decidedly preferable, however, if you could march the whole distance.
From the best information I have, you will find no difficulty in supplying your army until you cross the Roanoke.

From there here is but a few days' march, and supplies could be collected south of the river to bring you through.

I shall establish communication with you there, by steamboat and gunboat.