You need to pull a tanker behind you. Sure can't get very good milage. Would be nice to have one though. I call them ground shakers.
Our trike with carb'd 385hp ZZ4 will get 20-22mpg on the road. With 8.5gal in the main tank and 3.5gal in the reserve,range is not a big problem.
The 2012-later trikes with fuel-injected LS engines and 4spd overdrive autos will get 30-38mpg.