As soon as a tenant fails to pay rent, you can file a complaint without waiting 30 days or issuing a separate notice (unless your lease requires one).That being said, it could be a waste of time/fees to run to court because tenants in NJ may come even on rent (even after you win the eviction case) and then they won't be evicted: “The tenant shall have three business days after service of the warrant for removal to pay all rent due.”

The monthly payments are great, but the issue I am running into is what to do with idle cash.

The members here on BP that talk about STR auto-run systems didn't install those systems and find dependable cleaners & handymen overnight.

@Ana Escudero Property insurance renewals have been challenging the past few years, but there’s some stability with carriers heading into 2025.

Like could I still list run down properties but just sell them to investors?

if you pick a specific property and run the numbers maybe it will help. 

Long story short, over the past 10 years we have evolved into running a real estate investment club. 

You have to buy right, know where the market is headed, know ALL of your expenses and know what your various "outs" are before you commit to a property or you will lose your shirt.  

As always, please be sure to do your own research and run your own numbers before investing.

You can run ads directing people to your blogs or white papers, etc.