SR 200/A1A will be undergoing construction in stages over the next couple of years.
1) The section of SR 200/A1A from Still Quarters east to Rubin Lane will begin construction this fall. 
2) The SR 200 from Rubin Lane east to CR 107 is tentatively scheduled for construction beginning in Late 2015/Early 2016.
3) The Section from Still Quarters west to I-95 will start construction late 2016/early 2017.
Still Quarters Rd is just west of US 17; Rubin Lane is east of US 17 near the intersection of SR200/A1A and Miner Rd. CR 107 [SR 107 on the map] is also called Old Nassauville Rd.
For stages 1 and 2, Pages Dairy Rd. can provide a feasible detour around some of the work. Southbound Pages Dairy Rd. ends at Chester Rd., turn right onto Chester Rd. then left onto SR 200/A1A. Northbound turn right onto Chester Rd. then left onto Pages Dairy Rd. Turn right onto SR 200/A1A.
For stage 3 there is not currently a clear detour to avoid the construction.