There are various formula for crank size but most of them will come down to the same thing. For a guy your size (5'10" with short legs) you want a 170mm max. This will fit your legs and it will fit a frame without toe-clip overlap.
When sizing a modern frame, maintain adaquate standover but the critical dimension is reach. If you are between sizes, smaller is usually better than larger. Stems are easy to switch for different height/reach.
Check out
www.peterwhitecycles.com/fitting.htm
For an rough-stuff touring bike, check out the
Bruce Gordon BLT-X. It comes ready to tour with no modifications required and you get change from $2k.