The freight company I work for has retrofitted their fleet of Aero Commanders with TKS anti-ice system.
It consists of porous titanium panels installed on the leading edges of the wings, horizontal and vertical stabilizer, a spray bar on the windshield and slinger rings on the props.
We have a 17 Gallon tank installed in the aircraft for the system, and on normal setting uses 4.5 GPH, or 8.5 GPH on max setting.
Truely an excellent system, and well worth the investment if you anticipate flying in known/forecast icing conditions.
A company based in Florida also installed it on their 210s.
As for freight suggestions in a 206...maybe blood specimens, transplant organs, paperwork going to a centralized location - ie cheques, blueprints etc.
Good Luck