@Jeffrey Cervi Good morning from the left coast! I live in the Bay Area and have a vacation rental in Portland Oregon, and so while I have some competition, I believe Portland is minor league compared to Naples, that being said, here are my thoughts:
First, you have to make a decision what your goals are for your vacation rental and decide how much time and effort you are willing to put into the marketing and managing of the the home. Based on what I have heard from others, if your time is limited, you may simply want to find a broker who will take the rental and charge 20% to 25% of the rental to handle al of this for you.
Second, economics is a big part of the equation and without knowing how much revenue you generate it is hard to assess the best next step. For example, if you generate 50K per year in rentals, then 10K or more to an agent is a huge chunk and you could probably get to the same rental rent spending 2k to 3k per year in marketing. Likewise if you are generating 20K per year, then is the additional 1K to 2K of cash you will pay in higher management fees worth the effort?
Finally, you need to think through what else the broker provided for you and what that is worth? Did they do the booking, collect the payment, arrange for repairs and house cleaning, etc.? You need to figure out what else was included to help you put a dollar value on the cost.
As to your questions should you decided to take on marketing:
1) You can list it on the mls, see mlsmyhome.com, but I have no clue how effective this will be.
2) VRBO.com and Homeaway or not that expensive and should at least pay for themselves with a booking or two, so if you decide to go this route, you at least can break even. Remember to try the featured advertisements from time to time. In addition to the subscription level you purchase (which determines your search ranking), you can also pay extra to be featured as a top search result on a rotating basis for a certain period of time, so you may want to experiment with this as well.
3) Definitely get a web site - see myvr.com, super easy with lots of management tools included at a very low cost. Also be sure to register your business with Google, Bing and others, as well as putting yourself on yelp, I get a lot a traffic from these sites.
4) As to the rates charged, as mentioned above, this all comes down to how much your time is worth and the dollar amount in question. If the cost of a realtor is more than the time required to do what the realtor did, then you have your answer.
5) A PM is excellent, so then you will be limited to marketing only, so this may be viable
6) You have my thoughts, feel free to PM me if you have more questions.