Blackwater and assateague are two different hunting experiences. I've not hunted assateague, but live and work in Dorchester county. I love the marsh hunting. Comments about getting lost are on the money. Don't go without a gps, compass and map. There are tens of thousands of acres of state and federal land open to hunting in Dorchester. Blackwaters archery permit is over the counter and can be purchased any time. Their archery season is more restrictive than the state season so check dates before you plan to go. Fishing bay WMA, Taylors island WMA, and several thousand acres of Chesapeake Forestlands are all excellent sika hunting. A boat would open up a lot of opportunity, but is not required. Sika deer aren't quite as mysterious as folks might have you believe, but you will work for them and simply applying whitetail tactics may not give you the results you hope for. I think they are easier to hunt off the ground than whitetails. They respond well to calling which adds an exciting element. They love thick cover and stick to it for travel corridors. They bed out in the open marshes and move into the woods at night. Stands on the edge of the marsh but close to thick cover like phragmites or Myrtle bushes will afford a good view to scan the marsh but provide the cover they like for close shots when they come in. They are a hardy critter and their habitat is not conducive to blood trailing. I have regrettably lost a few well-hit sikas for unexplainable reasons. Last winter I made what looked like a great shot on a doe. I let it sit overnight and the next morning tracked it over 1.2 miles. Double backs, loops and crossed it's own trail half a dozen times. Tracked it with my GPS. Finally lost it when it went out on the open marsh and lost blood. Grid searches are next to useless unless you've got a dozen people holding hands as you cross the marsh. If you don't step on them you won't see them.
They are a ton of fun and am just thankful the whitetail and sika rut don't coincide with each other. I'd hate to have to choose between them! Good eats too!