Gettysburg is only a 35 minute drive from harrisburg and provides much more excitement than the actual civil war museum in the capital city.
You know how crazy the mid 1800's were and this is one of the locations where a lot of it went down. The small town caters to visitors and guided tours are pretty easy to find.
Don't have a specific person of tour to recommend but a visit is well worth it, and with a local college in the area, there are plenty of affordable eateries.
The site includes battlefield tours and well furnished museums.
83 South right out of the city brings right smack into routes 15S and 581. Stay on Rt. 15S all the way to Gettysburg.
Forrester street to the harvey taylor bridge also runs into 15S.
There's a ton of things to do in the summer in Harrisburg--some I've already mentioned, some that are definitely worth mentioning now.
Since they aren't things you can do all year, I guess they'll just go in one tip:
July 4th weekend
Pretty much this is a weekend with 5 stages of continuous music...all kinds, big names, lesser known artists. Combined with a crabfest, riverboat rides and other activities, this is a huge deal in Central Pennsylvania.
THE ITALIAN LAKE CONCERT SERIES
During the months of July and August, on Sunday evenings, you can listen to a variety of chamber, classical, big band and swing music performed at Italian Lake in downtown Harrisburg
This year, the dates are:
According to the website, the price is flexible to fit your budget. The purpose is to try to get people out for a night of affordable music--to concerts the may not be able to attend otherwise.
Labor Day Weekend
Kipona is a large festival held every year in Harrisburg...it's on the riverfront and includes the Regatta--boat races, an arts/crafts fair, LOTS of food (incl. the PA chili cook off, haha), music, huge fireworks display, and childrens activities