A 200 hundred amp service should be fine, unless your doing multiple simultaneous shooting in different parts of the structure. Dennis mentioned external sources that could cause noise while shooting, also be wary of how wind and rain may sound in the warehouse (especially if the roof is metal) if you plan to shoot while it raining. Good ADR will fix those issues, but just things to be wary of.
There are alot of ways to do stuff on the cheap end so you don't break your budget. You will find that being near a discount store like Walmart will be an absolute god send!! If you plan to use live computer displays (vs. cgi'ing it in later) on your bridge or whereever, you can pretty much get some old 10 year old P3 computers for free (or very cheap as people are dumping them all the time.) to run them. If you and your friends don't have alot of tools to build sets, think about renting vs. buying unless you need them all the time. You probably can get free pallets to use that wood as unseen framework to hold plywood set pieces up. If you do have stores like Home Depot and Walmart, think about getting credit cards for those stores as you will have greater flexibilty in your budget vs. paying cash for everything outright. There are alot of things you can do to save.