Okay, so there's the very handy
entweedle format, which will render your Twine 2.0 story into the twee format, but unless I'm being incredibly dense, there doesn't appear to be the option to import a twee file into Twine 2.0 (although there is for 1.4.2 on the downloadable version).
Is there any way import a .twee file into Twine 2.0? The reason I ask is because I sometimes find it easier to write/spellcheck in Twee, then use Twine for visualisation purposes. I could stick with Twine 1.4.2, but I really prefer Harlowe...