Leprechaun 260 DS fresh water system question

I just bought a new Leprechaun 260 DS. Like inside but the outside fresh water and winterizing system is an issue. The directions say to drain the water tank by opening T-valve hidden behind panel in driver side large storage area. The T-valve drains so slowly that after 1 hour at 1/3 tank fresh, it still read 1/3. Removed the whole side panel to see tank and it indeed had 1/3 fresh still. I finally closed the T-valve low point drains and turned on the pump and used the shower to drain the tank down until the pump was getting a small amount of air. I had already cut a hole in the wall so I can get to the pump. Anyone have any ideas how to get the T-valve to drain faster? Also, it has no gravity water fill. So how does one get water when the Forest Service campground has only a hand pump? Ideas appreciated.