I highly recommend the personal accounts of John Burckhardt . I don't know if this is the era you are interested in, (circa 1800), but should prove informative. As a sample:
A caravan departs for Medina once in forty or fifty days, principally with
India goods and drugs, and is always augmented by a crowd of pilgrims
who wish to visit Mohammed's tomb. These caravans consist of from sixty
to one hundred camels, and are conducted by the Harb Bedouins... ...The loaded camels take two nights to
perform the journey, resting midway at Hadda during the day; but, in
addition to these, a small caravan of asses, lightly laden, starts also
every evening, and performs the journey of fifteen or sixteen hours in
one night, arriving regularly at Mekka early in the morning. [When camels
abound, the hire of one from Djidda to Mekka is from twenty to twenty-
five piastres. In time of scarcity, or at the approach of the Hadj, from
sixty to seventy piastres are paid. During my stay, the hire of an ass
from Djidda to Mekka was twenty piastres. These prices would be
considered enormous in any other part of the Levant. Only fifteen
piastres are paid for a camel from Cairo to Suez, which is double the
distance between Djidda and Mekka.]
The accounts are quite lengthy, and only partially deal with caravans. If you would like to read them in their entirety, I have provided links at the end of this post; however, if you are looking specifically for information, and do not mind waiting an hour or so, I can collate and post a precis of of the information within...
C. Gosse
http://infomotions.com/etexts/gutenberg/dirs/etext05/7sria10.htm
http://infomotions.com/etexts/gutenberg/dirs/etext05/7arab10.htm
