You NEED money to do this folks, as a profession obviously, as a supplemental income / retirement plan definitely, and as a casual hobby I would still say probably.   

I'm looking for buy/hold property for rental income to supplement retirement income.

You are supplementing your tennats rent out of pocket.

“Z”; $2,736(no other box in Part III is used.)Supplemental information for the 1065 states:“CLASSIFICATION OF INCOME AS PASSIVE OR NON PASSIVE AS IT APPLIES TO THE IRC SEC. 1411 NET INVESTMENT INCOME TAX MUST BE DETERMINED FOR EACH INDIVIDUAL PARTNER.

Homestead, Mortgage, and whatever supplemental is all dropped off. 

I'd like to continue working in the tech field, and RE to me is a supplemental cash flow, as well as a diversification of the portfolio.The posts I've been reading in the forum, blog posts, twitter feed, podcasts have been quite encouraging, and I'm just excited to learn more from everyone here!

Get a long-term loan (12 years fixed) with a supplemental loan feature to extract the value add. 

I think getting into real estate investing could supplement your career as a union carpenter greatly.

I'd encourage you to seek out a larger brokerage that offers strong training opportunities for new agents and try and find a mentor within that brokerage that works more frequently with real estate investors as a supplement to your knowledge. 

Retire Early with Real Estate- Chad CarsonThis book details many investors who have retired or supplement their retirement with real estate.