Editor, thanks for the useful info. Was planning to do as much of Route 66 (as still exists) as far as Amarillo, but we certainly won't have a 4x4 to drive, just bog-standard hire car. I was just checking a normal car would be up to the job cos the ascent would presumably take its toll on some...and i'd read somewhere the road is a little hairy in places...not paved throughout.
Still deciding about Tombstone or Benson, or indeed, elsewhere...Chiricahua definitely on itinerary though. Yeah, you're right Tombstone will be pricey and prob. very touristy too I imagine. But a lot of fun I'm sure!
Looking forward to the burros at Oatman, though they may bolt at the sight of a couple of pallid Londoners.
thanks, tori