Update: I was down there mid June and stopped by the entrance to the GISP and spoke to the park office staff. The Island is still closed to overnight camping, but redfish road section (right side of the Island after you cross the bridge) is open to day activities and if your camping in the wooded section, you can go fishing over there any time you want. But there isn't any water or electric yet. The left side of the island (trout road I believe) is not open for anything including the pier.
So I asked what needs to happen before the island is back up and running for camping and the pier is open again. Honestly, they don't have a clue and I don't mean that as a jab at the staff. She said the roads need to fixed first and that's a TxDot (Tx Dept of Transportation) project. No work on the camp sites or the piers will be started until the roads are repaired and work crews have a good surface to drive in on.
I'm betting 3-5 years. It's been almost a year and the only real work that's been done on the Island has been the bathrooms and the covered areas have been cleaned out. Park staff got that done, but everything else is a wait and see as the roads are a TxDot project and I suspect bids will be put out on the rest of the work. I was told everything on the pier will need to be replaced except for the pilings, the bulkhead along the east part of the Island most likely needs to be replaced, and the water and electric services both need repair work or be replaced.
And there's the damage to Mustang Island SP and Galveston SP also. Powder Horn SP was supposed to open this summer per the original plans, but I'm sure all that's been moved way out till all three of the existing parks get the needed work done to get them up and going.
So Harvey's damage will linger for years to come as far as Texas State Parks along the coast. And will our parks get any help from those yahoo's down at the state capital? I seriously doubt it. They have a history over the last dozen years or so of robbing the fund that supports TPWD and the parks they manage. I asked my rep last time he knocked on my door about the funding issue for the parks. That was pretty much a waste of time. Got the song and dance about "more urgent matters" that need to be dealt with.