Currently, my published Adventures on the website can only be downloaded by using BaseCamp (beta's). At release, will there be an option to download Adventures via the web browser as a GPX file?
The short answer is no. The website is currently aimed largely at allowing non-Garmin users, e.g. friends and family, to see adventures without having to get BaseCamp. Downloading to the device currently exceeds the ability of the website. So for now it's a two-click download. Click the Download to BaseCamp button on the website, and then the Send List to Device button in BaseCamp.