Annual season pass holder for Carowinds...
The answer is...it depends. To the first question. To the second question, no, one full day (10am-6pm) is more than enough to see and ride everything if the park is average.
PARKING TIP: If you arrive early, if you want to hit BORG Assimilator first, park in the FRONT entrance of the park, if you want the other coasters (Top Gun, Thunder Road, etc., first, park at the BACK entrance)
Carowinds judges how many staff to have BEFORE the schools let out, usually around February when they have auditions.
If it is 70 and 80 degrees here like it was last year, that weekend will be packed.
If the number of staff is large, everything is open, all rides, including Water Works which due to early summer opened the second weekend of April last year (two weeks early)and the park is busy. If it is still cold, they will be on skeleton crew, have the BOGO (buy one get one free) coupons at Bi-Lo (grocery store) and the park will be empty.
WARNING! If it is cold in March, the water rides WILL NOT BE RUNNING! NOT AT ALL.