I have 71 acres and just about any combination of sites you can think of: wooded high and low ground, pond with woods and pasture, open pasture high and low ground, pasture with cedar windbreaks etc. I would aappreciate any advice on where to put these two hives and should they be close or separated? Thanks.

Brian

Probably the most agreed upon response, having to do with placement, will be the direction you face the hives. Generally it is advised to face the hives to the south and east. Of course, like your broader question, local circumstances could influence this answer. For instance this advise assumes your general prevailing winds are from the west (or perhaps, from the north during winter).
Low ground vs. high ground: Low spots tend to collect cooler air temps which may not be desirable [bee health & welfare] and high spots (such as a cleared knoll) are more susceptible to wind which will make working the bees more of a challenge.
Here may be the most 'controversial' comment I'll make and it has to do with the amount of sunlight the hives are subject to. Dappled light IS frequently recommended (and may ultimately, be the best answer to your question). After all, the long standing traditional, natural "home" of honeybees are hollow trees and they tend to be located in forests. But long ago I read comments from a long-time beekeeper and he advanced the idea, he thought his hives kept in full sunlight were always more calm/gentle and easier to work. Now, full summer sun is pretty darn hot(!) down here in H_ll(errr....I mean, Texas). Plus, I've kept hives in locations where they go into shade about 2 or 3 in the afternoon AND locations where they're in the sun all day long...I can't honestly say I've noted much of a difference in their temperament.
Close but not too close: If you're planning to actively work your hives and collect supers of honey from them, I'd say one of your more important considerations would be to locate them close enough to make the workload easy on yourself. But perhaps this isn't a consideration if you can drive your pickup (everybody's got a pickup, right?) to the location. And again, from a workload standpoint, I'd locate the two hives together - just a few fee apart to make working them easy.