Good luck with your hunt hugshe!
I live in MD and hunt Sikas occasionally. It's always possible to stumble into one, but most successful hunters and guides hunt over corn or milo feeders. My impression of Sika Deer is that they are semi-nomadic and don't really pattern like whitetails. They don't care about high tide or sunrise. They'll walk though deep water like it's not even there and will stick their head underwater to eat. They bed down out in the needle-grass (Black Needle Rush) on a high spot in the middle of the marsh and aren't really drawn to cover. The main reason to hunt from a hummock is to have a tree to climb. We see them just as often at noon as in the mornings. Most action seems to be the last half-hour of daylight, but they can move at any time.
There are a lot of Sika Deer in the lower Dorchester County salt marshes and quite a few in Blackwater National Wildlife Refuge, which does have some decent hunting areas. In spite of good numbers, one can spend a lot of time sitting out there without seeing deer.
I'd suggest getting a guided hunt if you really want to kill one.
The advice above about permethrin is very good, the swamp is unfriendly. Ticks don't care about deet. There are ticks (3 varieties), chiggers, mosquitoes (3-4 varieties), greenheads, deer flies and no-see-ums. It can be very difficult to sit still without a ThermoCell or being slathered in some sort of insect repellent. Most of what one encounters in October, while it can still be very warm out, are 'skeets, ticks and no-see-ums.
IMO, archery season is really the best time to hunt them, due to an abundance of deer during the early season that haven't yet reacted to hunting pressure. Crossbows are both deadly and legal. There is an early muzzleloader season for a few days in late October.
Be extremely careful how you shoot them, they don't bleed well (thick fur and fat) and seldom leave much of a trail in water. Belly down, they are about the same color as the mud and grass (average height 3 feet) and you can just about step on them before seeing them. If you hit one, watch him carefully and take care to mark the last spot you see it. The whole marsh looks the same and without a compass bearing and a landmark, it can be very hard to find the spot you think they're in.