I'm in Perry, GA. I actually called an electrician I do business with and he told me I could get the 25' temporary power poles new from Flint Energies for about $75 each. They ought to be perfect for this project. I'm in commercial construction and am about to demo a school starting this summer. I might try to get a couple of smaller beams from the school to use as support as well. That's a good idea.
In fact, there is another area on the land that I intend to build a bridge, but it is a much longer span. If I can score some longer steel beams that would be a great place for them.