I'm a resident of SD via the use of PMB. Each year in WY 5 months, 5.5 months in AZ, the rest in an RV.. If I sell my AZ home of 6 years, do I have to pay Capital gains?

[Hal_Al]

"In general, to qualify for the Section 121 (home sale) exclusion, you must meet both the ownership test and the use test. You're eligible for the exclusion if you have owned and used your home as your main home for a period aggregating at least two years out of the five years prior to its date of sale. You can meet the ownership and use tests during different 2-year periods. However, you must meet both tests during the 5-year period ending on the date of the sale." https://www.irs.gov/taxtopics/tc701

You appear to meet those requirements.

PMB? Private Mail box?  The question you didn't ask is: for state income tax purposes, what state have you been a resident of for the last 6 years. A definitive answer depends on my details (and is subject to interpretation).  But, on the surface, that appears to be Arizona.