Best way is local pickup. If you're selling, next best way is to leave it up to the buyer. Air freight is surprisingly inexpensive, and postal service can be a good deal for odd shapes and oversizes. I se the greyhound busses towing those parcel trailers a lot on the open highways, so I know they do it too.
The fuel tank can be problematic for anyone what with fumes and all. Take care to clean it out and describe it simply as "a tank" unless asked more specifically. Any that I have had shipped were scrubbed out really well or so old and shelf-aged that they didn't smell like anything anymore.