Note that under Pruneyard and Lloyd the limited purpose invitation standard and focus does not apply to private spaces. Thus it matters whether the land is private or public, not the purpose for which the public is invited to enter. The "limited purpose" test examines public or quasi public facilities (i.e., joint public-private parnerships), like airports, to determine whether they would be considered public forums for free speech purposes. (See Hari Krishna vs Lee)
Additionally, public sidewalks in front of stores are considered public areas because of the public easement to use the sidewalk. A private sidewalk is not a public area for free speech purposes (see Lloyd).
edit: deleted - the link did not support my claim.