Activism Questions about *place* and number of people

[liveoaktx]

First,generally speaking, is the shoulder on the side of a highway a public area? For example, I have frontage on my property that is maintained by the county that doesn't belong to me. In the town I live in, there's a highway and no sidewalks. Is it then okay to stand on the frontage area that I assume, like my property, goes back at least 10 feet?

I was told by the local postoffice that political discussion is not allowed on the grounds but it's okay done at the very front of the post office on the frontage.

Second, I know that in some cases, based on the number of people, that one has to get permits to assemble. what's that number? Does it vary?

Edit to add one more question re: Crawford- http://www.crawfordpeacehouse.org/protest.html

I remember hearing about some people, I think 5, that were protesting in Crawford and arrested NOT WHILE THEY WERE PROTESTING but en route-they won the case, but I notice that the above is listed on the Crawford Peace House site. What differentiates some people, say, going to downtown Crawford to protest from a *rally*?