I've been to both parks mutiple times... Of course since Carowinds is my home park, I've been there too many times to count... I digress
Carowinds
Get your tickets online for $29.99 instead of $42.99 at the gate, or if you're an ACE member I think you get in for half price!
My advise, go to North(front) gate first. Borg is sitting right near the front gate. If you go on a weekend, hit Borg first, just in case it breaks down later, or there's a really bad que.
I've always heard that people go around parks clockwise, so best bet is to go counter-clockwise.
After Borg, head on over to the back of the park, hit Thunder Road, Top Gun, etc. Also, if you have small kids you'll pass right by the kids section(s).
If the park is busy, I would advise hitting these coasters next, Hurler, Goldrusher, Ricochet, Cyclone, Vortex, in that order.
There's a Wendy's and some other fast food located at the front entrance to the park. My advice, eat there for your meals, it will save you a lot of money.
And a final word on Carowinds, when leaving for the day, if the traffic is terrible, exit in the FAR RIGHT LANE. You can go down and make a u-turn, or you can actually drive down about 2 lights, turn right on S. Tryon Street (Hwy 49), and drive a couple miles, and you'll come back to I-485. A right on 485 will take you back to I-77.
It will save you a lot of time if traffic is bad getting out.
SFOG
There's only one entrance (grrrrr), my advise hit Georgia Cyclone first (right by the gate), it seems to get busy later in the day. Then head right towards the back of the park for Superman. If the lines are like they were in 2002, you want to get on it early. There's hardly any shade, and it gets HOT at SFOG!!!
Most of the other coasters are all worth hitting, my favorites at Cyclone, Superman, Scorcher (my fav. standup) Batman, Mindbender, Scream Machine, Deja Vu and if you've hit all those, THEN ride Ninja. It gives you a headache sometimes.
Also, on food, if you drive out of the park, and take a LEFT, your first right there's a little side street, and there's Wendy's up there. (notice a pattern here) lol
As far as hotels, DO NOT stay at the La Quinta on that exit, We had a terrible experience. There's a new Country Inns and Sweets 1 exit West of Six Flags. I didn't stay there yet, but it looks much nicer. And there's more stuff on that exit too.
I don't know about discounts for SF, but check with AAA if you have AAA.
Have fun!