Trying to make a field work... Dimensions

Your situation resembles Columbia University's field, which is about 350 feet to straightaway CF.  I can't remember the height of the OF fences there.

I would say, If you have the option to make it how you want it. Then make it how you want it.

you have options that is awesome, I think non traditional is the way to go. I also believe most fields are to big. 

Something like a 310 to corners, 355 to gaps with 380 or so to center IMO are much better numbers then what we typically see. It puts home runs back in play and still isn't a chip shot. 

It seems like you have an opportunity to get a little creative which is always fun...and as a construction I can tell you moving the building is not going to be cheap endeavor. It will be much much much cheaper to rework the field. 

I don't know if the building is useful, a wreck or otherwise.  But, personally, I love a field that is a little different as long as dimensions aren't a joke.  I think 360 with a high fence would be cool.  Assuming the right fencing is used, it also gives you the batters eye background you want.  

If google street view is still accurate, it looks like you already have a bunch of demo work ahead like removing lights, electric, sheds, asphalt path, etc. I vote to relocate the steel building.

Yes, much work ahead. Eventually, we plan to build a new women's softball field and re-design the current field for baseball. After another look, we may be able to turn the current field clockwise 1 or 1 1/2 hours and make Building 13 into the left field wall. If we can turn the field clockwise in that manner, we can go up to 400 feet in CF and have a more traditional field with a LF monster. 

Now would be a good time to stand out there and check the sun. With that shift, would your hitters be looking directly into the sun? I'm assuming they'll play most games in the afternoon.
If that angle is no good, and you can move the steel building, you could spin the whole thing around so that hitters are facing the more traditional east-northeast (first base line along the road). That might also give you room for standard outfield dimension.

Yeah, I'll need to check the sun. Games are tpically played on Saturdays at 1 and 4 pm, Sundays 1 pm, and mid-week games at 4 pm.