The G Force ride has been removed, that is correct.
The Old Town described above is not entirely correct. There are two parks side by side-- Fun Spot and Old Town.
At Old Town you'll find a Big Apple and Windstorm type coaster, a drop tower, some kart tracks, a 300+ft. slingshot ride.
Fun Spot has more rides including the Sky Coaster, larger multi-level kart tracks, a small kiddie coaster, and various other mild to thrilling rides such as a screamin' swing. Nothing groundbreaking, but still interesting.
Both of these parks operate on a ticket basis, although it's also possible to do a wristband at Fun Spot if you find multiple rides you're interested.
This area is looked on Highway 128, about 10 minutes down from Sea World.
Also of possible interest is Magical Midway, located next to Wet n Wild near Universal. This has another 300+ft. slingshot, a star flyer, and 3 multi-level go kart tracks.
Another Fun Spot park exists nearby with no notable rides except for very impressive kart tracks.
As for coasters, Dania Beach is quite the drive away (4-4.5 hours depending on traffic). Also keep in mind the route most taken is the Florida turnpike which is very expensive. Boomers has 4 miniature golf courses, a massive arcade, and a few small rides outside. The main attraction is Hurricane, which is actually quite a good ride. I did an all-day wristband for $12, which turned out to be a pretty good deal. It wasn't overly crowded during my visit although they did seem to wait about 5 minutes between dispatches.
For the credit whore, there is also a small kiddie coaster at a place called Uncle Bernie's nearby. It's inside a larger Flea Market/Junk Shop area called the Swap Shop. We went solely to ride the coaster and ended up paying $3 parking and $3 for the ride; not worth it by a long shot.
The is a Wacky Worm in Jacksonville; again 2 hours from Orlando and not entirely worth it. There is a small waterpark there that includes a bowl slide and master blaster if interested.
At the Lowry Park Zoo in Tampa there is a small coaster relocated from Wild Adventures. Again, not worth the price of admission just for that.
All in all, I'd recommend you stay with the big parks, although a side trip to Old Town for the Windstorm is very much doable if you want the credit (the ride is ok, nothing special). For thrills, the sling shots and sky coaster are the way to go outside the major parks although keep in mind they aren't cheap: $25 slingshot, $35 sky coaster depending on # of riders.