If Nintendo's policies haven't changed since SmileBASIC on 3DS/WiiU, the Fuze IDE will be the only way to modify your code. Editing on PC or even emailing it to yourself is right out.
At least they say USB keyboards are supported. SmileBASIC on the 3DS is great until you realize you have to use the stylus for all input. I think I’d rather go back to TI basic on a calculator at that point.