I've been in Death Hollow in March, April, May, June and September. The odd thing is, the water level never really changed, even comparing the peak of spring when the Escalante was a brown torrent to mid September when the Escalante River was actually bone dry for a part of the hike. The water in Death Hollow stayed quite similar. I'm sure it peaks a bit with runoff, but it wouldn't be in March. Probably late April to early June when the high elevations on Boulder Mountain are melting fastest. My trip there at the end of April in 2006 was definitely the highest runoff out of all of my trips.
Like others have said, Death Hollow isn't an ideal destination in March. It's certainly doable, but it won't be nearly as enjoyable. It is an aquatic paradise and pretty much all of it is spent walking in the river. It's really, really good when it's hot! And depending on conditions and what winter is like, it might not even be possible in March. Last year was a very mild winter and
Cody &
Don did the air strip to Hwy 12 route through Death Hollow in late March,
photos on FB if you are friends with Cody. But if winter is a rough one, like it has been this year, there could be significant snow and ice in the shaded bends which would make it very difficult. Just for reference, check out all the ice we ran into on the Escalante on March 17th, 2006:
http://backcountrypost.com/forum/index.php?threads/willow-gulch-escalante-river-gorge.582/
Due to the narrowness and flow, similar conditions in Death Hollow could make for a very bad experience.
If I were doing 3-4 days in the area in late March with dogs, I would head down Hole in the Rock and do the lower canyons. The climate difference between lower Hole in the Rock road and the town of Escalante is significant. There is nearly 2000 feet of elevation difference between something like Death Hollow and something like Davis Gulch or Fiftymile Creek making that area much better for early spring adventures. As Bill said, Coyote is closed to dogs, but Scorpion Gulch, Willow Gulch, Fiftymile Creek or Davis Gulch would all be good options. Scorpion might be one of the best options as it has a good amount of overland approach and depending on your route, one dry camp that would be made much easier with mild temperatures.
Fiftymile and Davis Gulch can easily be combined to make a 3-4 day trip or do one of them and spend a day hiking down Hole in the Rock to Lake Powell. It's a fantastic area in that last 7 miles of the road. I'm probably heading that way myself in mid-March.
Willow Gulch is a little short for a multi-day backpack if you aren't combining it with Fortymile, and I wouldn't recommend Fortymile Gulch that early in the year.
So I think I'm a bit confused, are you doing Buckskin in March as well or in two days from now?