Fence,Shelter,and Straw

Hello everyone this last month I have done some thinking about where to keep my horse as it not working where I am now. I talked to my Grandpa and asked if I could keep my horse there since its right across the road. My Grandpa had built me a tack shed a tie rail and a really nice water trough but when he showd me when I was seven I said I didnt like it I dont know why and I wish I didnt say that bc I really regret it.Anywho to the point I asked my grandpa if I could and he happely said yes but there some changes that need to made.
1.It has no shelter so I need to build one ASAP.So what is the best method? I would like to put the shelter in the corner beside the tack room so I can use one side for a wall. What size should it be?
2.The fence is round rails all in good condition. Since it has been used a birth pen my grandpa put up wire so the the calves couldn't squeez out. It just happens to be the perfect size to get a hoof stuck so I either take the wire off or put up electric fence around the edge. Any other options?
3.My grandpa uses straw for his cows (bedding) so there seems to be an abundance that I could use. Should I use it for bedding? Will my horse eat it?
I am not moving my horse in til my dad gets a trailer so around march/April 2010 but I want to be prepared.
Thank you Tasia

A shelter doesn't have to be very big, 10x10 would be great. Just an overhang off an existing building would work. I have used straw as bedding when my girls foaled, they mostly sleep out in the open so I use nothing now. The problem with straw is it is more difficult to keep clean and your going to use more. If your grandpa has lots of it, go ahead and use it. One good thing about straw is its breaks down in a manure compost pile better than wood shavings.
As far as the wire, can you just remove it?
Sounds like you have a good deal going if you can keep your horse across the street. Plus I'm sure your grandparents will be thrilled to see more of you too.