* Cruising: This is the most common and formal spelling.
* Cruisin': This is the most common informal spelling, often used in casual writing or speech.
* Cruizin': Similar to "Cruisin'", this is another informal spelling.
* Cruis'n: This spelling is less common but still sometimes seen, especially in older texts.
Ultimately, the best spelling to use depends on the context and the intended tone.