Focus on one thing at a time. Maybe try some of the utility stuff first, like the new section settings, the new line guides or clear pipes. In most respects, building a level or episodes is much like in SMBX 1.3, it's just that now you also have an undo button and a selection tool. Coming to grips with some of the bigger new additions might help restore the flow a little.
Ideas are useless if you can't make them real.
All my assets from packs and episodes are free to use for non-Novaverse levels and projects, as long as proper credit is given.