If you're going to have wind in the area and grain in 4x5 isn't too bad for enlargements, HP5, Tri-x or Tmax 400 may be better than the slower films for landscapes. Using a staining developer for enlargements would help control grain a bit so PMK or Pyrocat-HD would come in handy for that extra stop or two of speed and easy printing. Efke 100 or FP4+ would both be superior for grain and expansion or contraction as David has already suggested, especially with architectural shots.

Do you process your own film with B&W? If not, stick with the one your processor knows best. Experimenting with films and developing would not be a great way to go. Ask your lab what they see the most in sheet films and use what they process in 4x5. Since film and developer combinations are so personal, use what is most available and familiar.