It often ruins the relationship.

That will likely be one of the side effects of improving your property and should be accounted for in your analysis.

You also will still need to manage your property manager  - ie, stay on top of expenses, ensuring your property is being managed effectively etc. 

If so they need a 'substantive relationship' with you before you put any money in.

The other way I fund deals with none of my own money is using a private lender that I have years of experience and relationship with and/or using HELOC and other business lines of credit.

Our clients have used 1031 exchanges very effectively when they have a property that turns out to not be the right fit for them.

For long-term planning, consider transferring the property into a trust to manage tax and legal complexities.This post does not create a CPA-Client relationship.

I’ve built strong relationships with agents, contractors, and other investors in the area, and one of my contacts informed me that the owner was considering selling but hadn’t listed the property yet.

Find someone where there is a personal connection and at some point your relationship now or later can benefit the mentor.

but that's dependent on your job, relationship, goals, commute... we can't advise you on that.