Hi, I'm Mike and I'll be glad to assist you.
1) What are the loads in Bldg #2?
2) What's the distance between the bldgs?
There are about 8 circuits there - I think 5 are 20 amp and 3 are 15. I don't believe these are connected however, as there is one of these overhead lines going to building #1, and another which continued on to buildings 2 and 3.
Can you just explain what you mean by "farm pole?"
Sorry, but one more question. The pole and the dawn-to-dusk light are there , though I don't see anything that looks like a load center. However, even with that set-up, you are saying I would still need a subpanel in building 2, is that right? if so, how did it get power before with no subpanel?