The rulings and terminology have varied somewhat, and doctrine specific to this provision will develop over time, but the Constitution probably couldn't have addressed this topic well before these decisions and the statutes and public comment that have accompanied them. Significant cases include Thornhill v Alabama, 310 U.S. 88 (1940); United States v O' Brien, 391 U.S. 367 (1968); Texas v Johnson, 491 U.S. 397,414 (1989); United States v Eichmann, 496 U.S. 310 (1990); Clark v C.C.N.V., 468 U.S. 288 (1984) West Virginia State Board of Education v Barnette, 319 U.S. 624 (1943); Wooley v Maynard, 430 U.S. 705 (1977) Miller v California, 413 U.S.15, 24 (1973); Reno v American Civil Liberties Union, 521 U.S. 844 (1997); R.A.V. v City of St. Paul, 505 U.S. 377 (1992); Wisconsin v Mitchell, 508 U.S. 476 (1993), and others. These can be found at www.supremecourt.gov/opinions/opinions.aspx
Applying Speech Doctrine
For example, to hire a hall is nonspeech conduct with partial protection under Amendment I as part of the package of speech conduct and nonspeech conduct facilitating the speech conduct of addressing an audience in the hall. As long as you don't charge admission, this package of conduct can now be placed on a scale of protected and fundable conduct by the ratio of speech to nonspeech.
If you charge admission it becomes private conduct (speaking before fans, not trying to persuade the public) and only the political portion of the advertising, which is seen and heard by the public, may be funded. If it is to be broadcast, that requires public funding, certification and regulation. It may not be broadcast without public funding in the covered zone during the covered time period before the election or floor vote.
At this point, the example has some protection as partial speech conduct that must be put on a scale to determine the level of protection it actually enjoys.
Speech conduct must be separated from speech itself, a very different thing where the Constitution's protection, or even state or local regulation, is concerned. Speech conduct has manner, whose invasiveness must also be determined for the amount of regulation it must submit to, as well as how much Constitutional protection it merits and what its budget can be if above the minimum. Speaking in a hall is not invasive. If you are pitying the FEC at this point, all these forms of conduct that include other forms can be categorized because their included conduct and level of invasiveness is standard.