The longer you get notice tends to be better for making plans.You need to look at INLINE rent comps in the area for BOX SIZES are that sq ft of similar locations to see what the average base rent is before CAM and see if it is currently above, under, or at market rents?

Check age of roof and parking lot as those are huge costs and even with tenant CAM you tend to have to spread the cost out for reimbursement over a long period of time so instead of doing that I get credit from the seller at closing to hold for those upgrades so it does not stress test tenants or affect existing NOI.

I have dozens of their cams at properties and the doorbell on my house.

HELOCs work more as a revolving line of credit, like a CC.I would recommend speaking with a local loan officer with experience with investment properties to better assess what makes the most sense for you financially. 

@Jason Cummings I don't know much literature, but there is a podcast/YouTube series named CAM Matters by Betsy Barbieux who is a long-time Community Association Manager (CAM) & runs several CAM education & training programs.

A HELOC maybe great, but is a large open revolving debt.

We use “CAMs” for MHP and split the w/s bill up pro rata for each occupied lot regardless of head count.

It does depend a bit on the time of year..........usually we have a revolving door with the unit rented before it is empty.

IIRC the ring floodlight cam is wired only.

Actually, because this happened to me I went and got a job as a CAM, or basically an HOA manager.