I've never been to the Alamo and most often use MF but I would imagine that a 28mm if you have one would give ample coverage. Some might want tightly composed details of just parts of a building and need longer lenses. Remember that perspective control can be an issue when photographing buildings. When I travel with MF I usually take my 50mm, 150mm and 2x. Although I have longer lenses, those keep the weight respectable and cover most of what I do. If I were driving from home I would take more and not be concerned with overhead bins. For sure take a tripod and if using B&W film some filters.

Some internet searching especially seeing photos of where you will be going would be helpful to have a lay of the land. enjoy your trip.

http://www.jeffreyglasser.com/