By mountains I assume you also mean woods too. By farmland I assume you are referring to fields and woodlots.
I stay away from fields . That's just how I hunt . I like the woods . The bigger the better .
Locate the roosts or general area the birds prefer to roost .
Locate the saddles and benches in that same general area .
Ridge tops that end in an abrupt point are favored places of interest too.
As you scout or hunt always read the sign the turkeys leave behind . Is there a lot of it or is it sparse? If there are forest roads there should be sign in those roads .
As for working a bird , I like to have plenty of understory or ground cover . Possibly a tree top or bank . I want the gobbler to come looking and when he gets close enough to see my calling position he's well inside my guns limit .
Timber that is very open and he'll likely hang up . This is where knowing the terrain ,,,,knowing where the birds do not mind going to ,,,,,and using what is there for blending in with your surroundings to your advantage is very useful in fooling a turkey to your gun .
When moving in the woods you need to move slowly and quietly . Not so slow that you'll never get anywhere, but steady methodical , taking steps with deliberation. Listening between steps without stopping .
Spend enough time in the woods and you will undoubtedly flush birds from their roost in an effort to gain ground on a roosted gobbler that you want to get to before fly down . It's part of turkey hunting . Sometimes a flush can be turned into an advantage for you by ridding you of the hens , or at least the eyes of birds other than your gobbling monarch .
I'm sure there will be others to offer up some good advice .