I have done several 3" body lifts, the 3" are about as complex as they come, steering extensions, fuel filler extensions, bending of the brake lines, chassis ground relocation, rad drop brackets, shifter extensions... first one took 2 of us, 2 days, 11 hours a piece, plus another 5 hours just for the bumper brackets, (we had issues with bent body mounts though) then I did 2-3 more after that, and got it down to a 1 day job for 2 guys, plus bumpers, which if it's not rusted, is 2 hours for 1 person
body lifts aren't hard, just a little overwhelming if you don't know what you're getting into. the steering extension was UBER simple, literally remove 1 bolt, separate the two sections of steering shaft, one extends a little and shrinks, so push it up, put the extension in, re install old bolt, and new nut and bolt, done! but like someone else says, it depends on make and model, yours might be a little different, but it shouldn't be any harder than that