for me, the ones that cashflow the most are the ones that I bought with 3% long term debt, they were new (low maintenance) and they are in high appreciating areas(just a bonus but does not impact cashflow).

I'd recommend speaking with local specialists in your target market to look at multiple investment options side-to-side.Lastly, some of my clients have been encouraged to stay away from HELOCs unless they expect a lump sum (inheritance, sale of other asset, bonus, etc.) to pay off the HELOC in the next year or 2. 

Yes they are a nice bonus, but you could find yourself on the end of a lawsuit due to a guest getting injured or even killed.

More work, more time but you can take advantage of a nice cost segregation / bonus depreciationThis is the truth! 

Remember, investing 200,000 into an ADU won't likely increase your properties value by 200,000, but the rent potential is a great bonus.

@Cate DeBates Triple Net commercial lease is a huge bonus!

Bonus if you have any advise or pools. 

That one will take a year, but then it will get 25K a month on 2.5M, and there is an RV park as a bonus.   

But it also means you have virtually zero bargaining power as the seller can reuse any and all repairs and just keep your 6 months of rent as a bonus. 

If you go with the partnership route1) You need to manage the money going in and out of the business bank account.2) File a partnership return and be responsible for issuing K-1's3) make distributions to you and your partner for cash flow that you receiveYou will likely spend many hours on a nice gesture.I may want to consider instead to give a christmas gift or a bonus for early completion of projects.