Penny,
I often use one light only with a parabolic reflector for location shoots and set it high -- about 7' off the floor -- just off of center. It wraps the light just fine and the high location makes for no shadows.

For other shoots, I'll use two ABs bounced off of silver umbrellas and, at times, I've used my 580EX and just bounced it off of white ceilings or walls (or both). Since you often don't know what you're going to have to deal with on location, I tend to bring everything but the kitchen sink and then use what works for that particular spot.

Here in Florida, garages are not really an option since we have temps in the 90's pretty much all year round but any room in a house will work and I especially like to use rooms that the dogs are comfortable in. And, if they have a special chair or couch, I'll drape that piece of furniture with the backdrop so they are even more relaxed. Learning what you can -- and cannot -- do with your given lighting options will give you much greater flexibility when you walk into that "impossible" location .

Jim G.