I draft cars whenever possible, but it's also not like drafting a cyclist, you don't need to be 6 inches off the bumper. you can leave a nice safety buffer and still get most of the effect.

I think the best thing I've ever drafted was a landscapers enclosed trailer. It was super low to the ground, but still about 8 feet high. This thing was the greatest draft I've ever experienced, and I wasn't anywhere close to a dangerous distance behind it.