IaAcres , :ditto: to JDFANATIC and look into the 4000 Series , especially since you mentioned (Money is not a problem since it will to paid in cash.) ...To me, the question is less a 3520/3720 than a 4x20 tractor vs that series. That is a lot of acres and if the larger frame tractor is acceptable, I would be looking at it.
Good Luck on your Deere Hunt !!!