Don't forget the 5-20 adapter - 33% faster charge than the 5-15 that comes with the car on 120V household circuits. And so, I'd recommend a 20A rated extension cord. I've actually used my 5-20 adapter when travelling, haven't yet used my other adapters, but each person's usage is different.
While the 14-40, 10-30 adapters are nice, you might find you need an extension cord to get access to those plugs should you ever want to charge from one. And that means a 50A extension cord. And home made adapters. You can go pretty deep with this. Check out this document if you really want to see how it all works. Note, most people don't need to go to this length...
http://cosmacelf.net/Home Made Adapters.pdf