At the end of August, the track will still be running in Saratoga. It's a 20 minute trip on the northway and even if you don't like to gamble, it's a great place to people/horse watch.
There's a nice bar/restaurant on a little lake called Glen Lake...The Docksider. The food is good (not spectacular), and the service a little slow. But...if you aren't in a hurry it has a fantastic view. They have a great covered deck. The perfect place to sip a drink and have something to eat. I grew up there. My grandparents used to own it (quite a while ago) when it was called Sullivan's Pavillion. My grandmother still lives about 8 houses down on the lake. If you take a right out of the campground, take another right on Oxen Hill Rd, and a right onto Glen Lake Road, it will be about a mile down on your left.
My mother just went to another new restaurant nearby. I think it's called the Cherry Tomato. It's on 149 (just take a right out of the campground). She said it was really good.
Suttons has a nice breakfast and a really nice gift shop & bakery. Take a left out of the campground and another left onto rte 9. Go past Great Escape, it will be a little further on the left.
Almost across the street from Suttons is Skateland. They have go-carts and rollerskating.
A little further south on Rte 9 (same side as skateland) is a drive-in movie theatre.
Of course, there's always the village of Lake George. There's a couple of beaches (one's free, one you pay), arcades, souvenir shops, bars, and people watching.
The campground you picked also has a lot of activities. You probably wouldn't even need to leave and you would find plenty to do.
Oh, and Prospect mountain is a nice place to drive up and have a picnic...beautiful views. There's also a lot of great hiking in the area.