I have to say at the outset that the advantages gained by using a non-theatre space for a peformance are seriously outweighed by the practical concerns that have to be dealt with. While there is no question that an unusual theatre venue has an appeal to all but the least adventurous of theatre-goers, (there is bound to be a box office advantage just to satisfy the curious as to how the space is used - especially if it is a familiar location such as Union Station) there are nonetheless a large number of factors that have to be addressed when moving outside the confines of an equipped theatre. But the difficulties are not to be underestimated. Here is a list of the concerns that must be faced.

audience related concerns:

Access

how do you find the theatre

Signage

especially if the space is not a familiar location.

Distance

how long it takes to get to the location.

Parking

how far do you have to walk

Disabled access, washrooms and other amenities

Heat/air conditioning

Front of house/tickets/box office/lobby

Emergencies/first aid/stage management-related crises

Notification of appropriate dress, footwear etc.

especially if there is a lot of walking between scenes.

performer related concerns:

backstage amenities:

green room. dressing rooms. transportation

(For example, the dressing rooms are a tent on the shore and there is a twenty minute boat ride (in the dark) to the section of the designated performance area where you wait (in the dark) for the performance to begin)

heat and other comfort-related items

acoustics

sightlines

for example between orchestra-soloist-conductor-stage manager

crew concerns:

shop facilities and related access for materials delivery (for work done on-site) and delivery of finished set elements, costumes etc.

does the site have to be returned to its normal function between performances?

Storage ( Is the backstage area set up to accommodate set/costume changes, prop storage etc.) distances eg. between wardrobe area/dressing rooms and stage

masking the unmaskable

the three thousand little things

technical concerns:

electricity - usually has to be brought in

(especially the Science Centre... The 20th century high-tech displays were not exactly supportive of our attempts to create a sense of dynastic Egypt. Because the audience moved from location to location, the amount of architecture and especially display material that should have been disguised was impossible. Lighting can do an enormous amount to limit what the audience sees. In these cases, the task is comparable to a film location situation though usually without the film budgets. )

hanging positions for instruments - usually have to be built cabling must be rented in vast quantities

positions for control boards/lighting operators

In short, virtually everything that is needed, from audience seating to dressing room mirrors to wings and masking, must be brought to the space and installed.