Sitting close to the Jacksonville-Kingsland trail, this trail winds right through Jacksonville right to the coastal area
We'll just go ahead and mention it: Jacksonville is NOT a cycling friendly city. In every list of most dangerous cities for pedestrians (cyclers/walkers/joggers) Jacksonville sits high on the the list with other Florida cities rounding out the top five. Florida's road systems are not friendly towards pedestrians due to many reasons – The heat, the lack of bike lanes in areas and Florida motorists themselves. You often have to fend for yourself by riding on sidewalks. With that saying – There ARE safe ways to cycle to and from work - If you live in the right location of Jacksonville!
Go to Jacksonville's Apartment Guides page to see the map of available apartment communities. From here is where you can compare your work/class locations and compare with prospective apartments communities. Take a look at the Google Street View shot of the area (drag the little orange guy on the top left of the map to the street) to see if bike lanes are available in the street.
What about trails?
Jackonsville features several bicycle trails with many in the vicinity of UNF and Military bases. These trails are convenient detours that take you right through Jacksonville to where you need to go. Look out for the Jacksonville-Baldwin Rail-Trail among more convenient trails that dot through the area. A full list and map here where you can compare this map to RentJax's apartment map: http://www.bikemap.net/regional/United%20States/Florida/Jacksonville#lat=30.34499&lng=-81.72126&zoom=9&type=6
Storing your bike
While Jacksonville is by no means a dangerous city in itself; there is crime like any other city. You are best off storing your bicycle indoors when not in use. These are high valued targets by any amateur thief so it's not worth the trouble of keeping it out in the open. Look out for an apartment that offers an elevator so you don't have to haul up your bike everyday. A large balcony is also great for storing a bike. Also look out for the Parking option in RentJax Guide for covered parking garages just in case this isn't an option for you!
Weather
It goes without saying, Jacksonville can get hot and humid. Be careful you aren't over-exerting yourself out there. You may be saving money on gas but you may also be that person at work drenched in sweat. Cycling isn't the best option if you decide to live way across town. Cycling is still a great option if you live close or near these coveted trails!