Don't know if this is too late and too tangential, but we just finished the process of turning our house in the Tampa area into a AirBnB/VRBO property. I was going to try to handle the bookings through those two websites, and then have my neighbor down there be the go to person who would over see the cleaner, call handymen etc. I was thinking about a monthly retainer or a percentage of the rental income. But she doesn't do this for a living and I think we both realized it was more of a job than she wanted to take on. I interviewed a couple of management companies who would take 20% of the rental income, as I remember, or maybe 50% if they did the booking. One scenario was that they would charge me $100 a month plus 20% of the income, but I would handle the bookings, and they would handle the broken toilet at 11pm.
Eventually I ended up hiring a couple who are renting out a few properties on AirBnB since they are very short term rental savvy and specifically on AirBnB/VRBO, have a team of handymen etc whom they can call, and can go by the property as needed. They are now handling everything including adjusting pricing as needed to increase bookings during slow seasons, paying the cleaner and telling her when cleaning is needed, and for this they are charging 20% of the income. We have set up a joint checking account which i keep topped up around $2k- they take their fee, the cleaner's payment, etc. out of that. They also handle returning the security deposit to the clients once my cleaner calls them to let them know if there are any problems.
One thing that is nice with this is that they encouraged me to go from a week minimum to a 3 night minimum since that increases the probability of finding clients and at the beginning I need to get some reviews. Since I charge clients separately for the cleaning, there is no cost difference to me to rent it for 3 nights v 6 or 7 nights, other than having to wash the linens and provide a fresh set of toiletries twice in the week as v. once. My cleaner is happy because she is getting more money.
So far it's great, since I am currently in Guinea working on Ebola and not on line that much!
Hope this helps as at least a data point in your thinking......best of luck!