when you get into Virginia get on I-81 North until you get to the town of Harrisonburg then take Route 33 east into West Virginia this is a very scenic drive with many pull offs and great vistas without the crowds you will find along Skyland Drive or the Blue Ridge Parkway.
Once into West Virginia stay on Route 33 until you get to the town of Harman and turn right onto Route 32 North. In the town of Davis West Virginia is a place called Blackwater Falls State Park. If you are into water falls this is a MUST SEE. There are dozens of water falls in the park. There is also a very nice lodge with modest priced hotel rooms and a restauranthttp://www.blackwaterfalls.com/
I have been there many times, my favorite set of falls is right behind the lodge along Shay's Run. The advantage of Blackwater is that there is usually good water here in the summer when many of the other falls along the Blue Ridge are quite low or even dry.
From there continue on Rte 32 north until it turns into 219 North and head into Maryland. If you time and you like water falls you can make a quick stop at Swallow Falls State Park just outside of Oakland Maryland. There are 4 nice waterfalls there that are a very short walk from the parking lot. From Oakland continue up 219 North until you get to 42 North and take that to I-68 West which will take you back into West Virginia. Take I-68 to Morgantown until you get to I-79 North. Stay on I-79 north and cross into Pennsylvania you will pass Pittsburgh.
If you have time there is nice state park on Exit 99 to the north of Pittsburgh called McConnells Mill State Park. There is a very nice covered bridge there over a very nice creek. There are also several nice waterfalls there but they are a bit of a hike. You could turn off the highway take some hots of the bridge and be back on the highway in a half hour while the waterfalls would take 2-3 hours.
Keep on heading up I-79 until you get to I-90 in Erie, Pennsylvania. Take I-90 east towards Buffalo just before you get to New York State on the other side of Erie you will come to the town of North East Pennsylvania. Take Exit 41 which is Route 89 and take it north towards the town of North East. Route 89 will turn into Lake Street and then turn into Freeport Road. It ends at a "T" with Route 5. Take route 5 east towards Buffalo. The drive along route 5 is very nice as it runs right along Lake Erie. Lake Erie is one of the Great Lakes and is so large it looks like the Ocean as you can not see the land on the other side. This is wine country and there are many vineyards with the lake as a back drop that make for awesome landscapes. In the town of Westfield NY just beyond North Portage Street you will come to a large marina and a large public dock. There are often nice boats here on the water. There is also a nice sandy beach and very high cliffs along the North Side. All of these make for great shots and this is a great place for sunsets as you get a westerly view of the water and can see the sun dip below the horizon.
Beyond Westfield you can continue along Route 5 or head back over to I-90 by taking North Portage Street. I-90 in New York State is called the Thru-Way and is a toll road. Take I-90 up to Buffalo New York and follow the signs to Niagara Falls. On the American Side of the Falls that state of New York has a very nice State Park that is a lot more natural than the Canadian Side. Take the Rainbow Bridge in Niagara Falls and follow the signs to the QEW (Queen Elizabeth Way) which will take you to Toronto. Once you cross into Canada do not plan on coming back into the USA unless you want t spend a lot of time at the border. It is quite easy to get into Canada these days but a pain to get back into the USA. If you are going to stay the night in Niagara Falls you will find it cheaper to stay in the US in either Niagara Falls New York, or in the Buffalo Area.
I live in Erie, Pennsylvania and have lots of family in Harrsionburg Virginia, and lots of friends in the Buffalo Area so I am very familiar with this trip. Feel free to contact me if you have any questions I will be happy to help.