I am working on a history project for school and cannot seem to find information on the length of a journey on a ship from England to the Charleston area of South Carolina in the early 1700s (1730-1740). Additionally, would the upper class travelers face different conditions from the middle class?
How long would it take to travel from England to the colonies in the early 1700s?
The distance from England to the Charleston area of South Carolina is:
Speed of ships in the 1700's was around 5 knots1.
To convert all in same units: d = 4010 mi = 6453 km and u = 5 knots = 10 km/h, to get the time we use the following equation of motion:
t = d / u = 6453 / 10 = 645 hours => 27 days in the ideal situation. However, in reality weather conditions like storms, ocean currents2 etc, would prolong the journey up to 6 - 8 weeks.
Would the upper class travellers face different conditions from the middle class?
As an example of the conditions faced by the middle and lower class:
...The passage to America was treacherous by any standard. Many of the immigrants were too poor to pay for the journey and therefore indentured themselves to wealthier colonialists - selling their services for a period of years in return for the price of the passage. Crammed into a small wooden ship, rolling and rocking at the mercy of the sea, the voyagers - men, women and children - endured hardships unimaginable to us today. Misery was the most common description of a journey that typically lasted seven weeks...
1. Dependent on their size (Hull speed) and the winds. .
2. About the same time Ben Franklin measured the (6 degrees) warmer temperature of Gulf Stream and created a map which would turn out to be very useful to sailors ("riding it the trip would shorten with a week").
 Mittelberger, Gottleb, Gottleb Mittelberger's Journey to Pennsylvania in the Year 1750 and Return to Germany in the year 1754 (published by the German Society of Pennsylvania 1898)
As mentioned in the comment section there are alternative routes, in fact 18th Century British shipping routes visualised using modern mapping technologies look like:
which includes the one proposed above, however, if the general idea is understood the above calculation could be applied to any of the shown routes.
Dutch shiping routes 1750-1800 visualised using modern mapping technologies are closer to the proposed in the comment:
together with Spanish shiping routes in the same period 1750-1800:
When John Adams sailed to France in 1777, the voyage took six weeks.
Accompanied by his oldest son, John Quincy, Adams embarked on a six week crossing of the Atlantic.