What kept the treasure seekers from departing as quickly as they hoped?

They were kept from departing for no other reason than tying up loose ends. The doctor needed to take care of his practice, and the squire needed to finish up some work.

"IT was longer than the squire imagined ere we were ready for the sea, and none of our first plans--not even Dr. Livesey's, of keeping me beside him--could be carried out as we intended. The doctor had to go to London for a physician to take charge of his practice; the squire was hard at work at Bristol; and I lived on at the hall under the charge of old Redruth, the gamekeeper, almost a prisoner, but full of sea-dreams and the most charming anticipations of strange islands and adventures."