Beleive it or not, it has been my experience that the "internet price" on most car dealer's ads is usually CLOSE to as low as they will go.
I have bought a few used cars, gone in without telling them what the price I saw it listed for was, and had the dealers come out and quote me $1500-3500 higher. One, the "internet price" was $8500, the price written in huge letters on the windshield was $11,990.
Used car dealers hate the internet. They know they have to put a competitive price online, since you'll have easy access to compare 100s of other cars. If you walked into a car dealer and just picked any car off the lot they would totally screw you. (as above, to the tune of a few thousand dollars)
Now having said that - there could still be PLENTY of room to negotiate in that price. With such high mileage, I'd hope so. The important thing is to find comparable vehicles for sale and go in ahead of time with a number in YOUR head that represents what you think the car is actually worth.
Also don't forget that you are in a great market - if you don't find anything that fits exactly what you want in tampa, there is always sarasota, orlando, miami within a few hours drive....
And remember, while a car with 160k miles "doesn't seem too bad" .... once you put 40,000 more miles on it - NOBODY is going to want it - your resale value will drop dramatically...