Question: Are weekend real estate directional signs allowed along State highways?

It will depend on the state you’re in, or how strict the enforcement of bootleg laws are.

Directional signs are used along the highway directing traffic to an event, sale, or home for sale, and are often called “bootleg” signs, because they’re typically considered illegal (the name comes from the Prohibition Era of the US’ history when “bootlegged” liquor was sold across the US by illegal producers.

Question: Is it OK to put my sign on the highway Right-of-Way or State property?

No. Not in any state or 1st World country that I’m aware of can this be done. It is considered a potential hazard at worst and pollution at best.

Now, if you want to put a sign pretty much anywhere you want, move your business to a 3rd World Developing Nation such as the Dominican Republic or Honduras or Indonesia, where anything goes.

The interstate highways,