TOD:
I grew up in a small city in South Carolina, so "roadshow" presentations weren't the norm. Films did have lengthy stays at times (usually not more than a month), but we were always aware that a film had been a roadshow because the newspaper ad would tell us that this film "the same film as seen in its roadshow engagements" (which were generally in the large cities in America).
Of course, the big lie was that they weren't the same as those shown in roadshow engagements, because overtures, intermissions and exit music will have been removed. That way, they could squeeze in extra showings.
Roadshows were generally played twice a day.
But...when "The Sound of Music" was slated to play at our Carolina Theater, we were informed it was coming and that it would be reserved seat only. I well remember paying for my reserved seat at the box office two weeks ahead of the first night.
I then attended the first night showing and was, along with the rest of the audience, absolutely enthralled.
After that, many other films opened as reserved-seat roadshows including "Funny Girl" and "Fiddler on the Roof" and "Camelot". Generally just musicals.