Without a doubt, hit Jazzland. I was just at both parks less than a month ago. Mega Zeph was the best coaster of the whole trip! (SFOT, SFFT, SFAW, Jazzland) The only trouble is that the park is VERY small and you may run out of things to do. Astroworld did not impress me in any way shape or form. Maybe because no less than 4 coasters (Ultra Twister, Greezed Lightnin, Texas Tornado and Serpent) were down all day. Texas Cyclone was good, but Mega Zeph blows it out of the water!
Looking at your track record, you have not been on a CCI. Mega Zeph would be a great way to fix that!
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"X" marks the spot in 2001!