I live in Fort Bend county. There is a man several miles from us who keeps his cattle on land without a well. He hauls water in a large tank on a trailer.
http://www.tractorsupply.com/leg-style-storage-tank-325-gal--2137463 He parks the trailer and fills his trough. He has been doing this for over 15 years.
My suggestion would be to invest in a generator and buy a spot sprayer to wash the cattle. You can run it off of the generator.
One thing to think about concerning building on the land. Every permanent structure that you build (posts in ground) will belong to the land owner. You all might want to look into using portable structures (stalls and pens) so that should the FFA members have to move again, all will not be lost. There is nothing much worse than sinking money into something and be left without anything to show for it.
Also depending on where the land is located, I would make arrangements for a parent to bring the generator and spray rig to the place. Don't leave it there, unless you have a very secure building like a used cargo container. We have a 40 foot container. It isn't pretty, but it is secure when locked. I think that we bought it from a person in Bellville. It was under $2K delivered.
Mark Switzer Auction Sevices (Phone #: 979-885-2400 ) is having a sale on July 28 at 9 am in Sealy.
Farm, Ranch, & Construction Equipment Auction - 1036 S FM 331, Sealy, TX NOTE NEW STARTING TIME
You might be able to find panels and supplies there.
If you want to tell me where you actually are in a PM, I would be happy to see if I can help you.
Good luck!
ETA: I've been thinking about this. When the kids scrambled, they represented their school's FFA Chapter, so a scramble heifer is actually a school related project. So it should be allowed in the District Ag Barn. At least in my opinion.