i live in Austin haha. Emos east, haven, republic live, Austin music hall, antones, kingdom, the parish, etc... all places around Austin that play EDM events. for example, kaskade already played or is playing very soon at kingdom, and borgore is at republic this Friday. Austin Music Hall and Emos East play all kinds of music but a lot of EDM and generally bigger shows. Guys like Bassnectar and Excision play at Austin Music Hall when they come around. Also, check out stubbs, as many good artists go by there. Big Gigantic and Lotus were both there this year.
If they ever have it again, one thing you should definitely check out is Nocturnal Wonderland. Ive heard it compared it to things like Bisco and Electric Forest in a sense that it is very hippy vibed and chilled out. less of a Bro-ish crowd and more of a nice, rave, plur crowd. im sure you will probably end up at several of the same shows as me.
Also, if you come up with a few hundred, there are PLENTY of great shows to see during SXSW. went for my first one this past year, and am going to do it again for the next several years. who knows, maybe ill play at SXSW one year haha. if all goes well (really well).
EDIT: for 420 I barely did anything. I went to a warehouse rave after midnight until 4 AM over at a place on lava hill road which is south of the airport. I skipped out on Marley Fest and all of the 420 festivities.