We have rented a very large home on the beach in Hilton Head for one week in July. Would like to take a daytrip to either Savannah or Charleston, or any other places of interest. What would you recommend? And should we take a tour while in one of the recommended cities? Thanks for your help.

There is a tremendous amount of information here about both cities. You'll find many suggestions if you do a search on the two cities.

EBR- You are only 1 hr from Savannah- it is a longer drive to Charleston....

You do not need a guide in Savannah..Head to the riverfront area for things to do....

Savannah makes a great day trip since it's so close! Charleston is further, so get an early start on the day, and take the road that hugs the coast. Not as quick as the highway, of course, but the scenery--low lands and marshes--is enchanting. Another nice day trip is Beaufort, SC.

Make the drive to Charleston - It is worth the extra drive. Charleston is wonderful city. It has great restaurants, wonderful historic sites, great boat trips ( I love the sunset cruise) Churches, homes and shopping ! I love this city

Well, Charleston is farther away and Savannah is actually less than an hour, well... less than an hour if I'm driving and theres no radar Both are great, but I'll suggest you do Savannah AND also visit dear little Beaufort, which is also a straight shot from HH on a somewhat {and thank God currently being widened!} scenic drive through woods and over the river, literally, and into the historic district. If you cant make Charleston then Beaufort is a good choice because its like a tiny little Charleston with similar architecture, similar great people, and unfortunately TOO similar real estate prices lol Eat at Emilys or the Bank or the Beaufort Inn.
Take the Ghost tour that leaves from their very nice waterfront park area. Take a carriage tour with Spirit of Olde Beaufort tours from the visitor center.

Savannah has loads of tours and since it'll be July you may prefer to take one if its in an air conditioned van!

While on HH be wary of the slowest moving traffic on earth and the many alligators! I dont know what happens to people on HH, but they suddenly lose their sense of direction once they pass the Saks 5th Avenue or maybe a little further down. Have a great trip.

Are you driving or flying into Hilton Head? If you are driving, maybe think about adding a day or so extra to your trip and do a day trip to Savannah and an overnight to Charleston. Both are great cities. It is like trying to decide between emeralds and diamonds.