Yes, Windermere FL is safe. How Safe? Statistically safer than 65% of the cities in the United States and safer than over 80% of the cities, towns etcetera in the state of Florida. I took the photo above which is of the old police station in Downtown Windermere FL. This is one of the few cities I have lived in where I do not have any concerns about my vehicle. Not that crime does not happen here but it is very rare.
What nearby areas are safe? Well Gotha to me is just an extension of Windermere. However the further north you go the more crime I believe you will possibly see. The closer you get to the amusement parks the more people from other locations you will see and the more people you see will be passing through. I doubt your gut feeling will tell you it is ok to not lock your car etc. That gut feeling will be correct.
Southern Winter Garden FL aka Horizon West is another location I visit very often and have never witnessed a crime. I have actually witnessed robberies etc when I lived in South Florida. In fact I witnessed them far to often which is why we did not stay. If you are so blessed that you get to live in a gated community in Winter Garden or in the Windermere FL you may very likely go the rest of your life without being affected by crime.