Unit B is currently being remodeled and the current owners are accepting applications for that unit at $550-595, I am trying to negotiate with them to either only lease it month-month or rent it for what I am wanting to charge rent for.

This place is in Inglewood CA where prices are going up like 8-10% per year, so it will (almost) definitely appreciate considerably over that time (Rams/Chargers stadium being built, Clippers moving in, new entertainment developments, overall gentrification etc. 

However, make it very clear that if they stay into September then you will charge rent for that month.You can also consider prorating their rent for whenever they move out. 

You can usually run a few lamps, alarm clocks, phone chargers, etc no problem, but if the tenant wants to (say) use a hair dryer in the bedroom, they might end up popping a breaker.One disadvantage to a window unit, especially if it's on the first floor in a less-than-great neighborhood, is that it's relatively easy for the bad guys to push it into the house from the outside, and then climb in through the resulting hole. 

Maybe even put in a car charger? 

What online program or website do you guys use to keep track of all your properties and even charge rent through those websites.

How about an outlet for the RV so the owner can plug in a battery charger, water tank heater, etc?  

Free - we won't even charge rent.

If we spoke, and I agreed to let you out, I'd drop the fee, but still charge rent.

A judge would take a very dim view of trying to charge rent after they left.2) You have a time line for returning the deposit or providing an accounting?