Hi there,
We live about 10 minutes from Six Flags. There are no hotels in Jackson itself.
There is a really nice looking Ramada Inn in Lakewood on the junction of rte 70 and rte 9.
There is also a nice Best Western in Lakewood on Rte 70. Both of these are about 15-20 minutes to Great Adventure.
There are a couple of hotels in Toms River. A quality Inn on rte 37 east and a HOJO's also on Rte 37 but on the west side. Tom's River will put you at about a half hour drive.
Hope that helps.