The municipality of Florina is situated in northwestern Macedonia, Greece and consists a border of Albania and the Former Yugoslav Republic of Macedonia. Its capital, Florina has a population of 15000 habitants and is surrounded by Mount Varnountas and Vitsi.
While in Greece, to avoid hostility, you could refer to FYROM as "Skopje" or just say the town you have travelled from. This is currently quite a sensitive issue.
There are three trains every day between Thessaloniki and Florina and vice versa. The journey lasts 2,5 to 3 hours and costs 10€ one-way or 16€ return (with various discounts for students, youths and other groups). There are also trains from Athens with a connection in Platy. Timetables available on TrainOSE website.
There is no public transport from or to Albania or FYROM, unless you get a taxi.
From Bitola it is about 30 km, and takes a little over an hour by taxi. Macedonian taxi drivers require a special permit to operate in Greece, and they might use this fact to quote you up to €40. You should be able to knock them down to €25 or less. If they don't have a permit, they might offer to take you to the border for just a few euros, but you then have to walk between the border posts (800m) and hope to find a Greek taxi. Alternatively, they might take you all the way but pretend that they are a private car once in Greece.
By car, it is very easy to reach from Thessaloniki (~2h), Ioannina (~2h), Athens (~8h).
Florina is a small town. For this reason, it is highly unlikely that you need a car to explore the town itself. If you want to visit nearby Prespa or any villages, you 'd better rent a car. There are local buses for some villages, but they are not very frequent.
Don't miss the chance to buy some local red peppers, which are widely known in Greece. You can also buy beans from the nearby region of Prespa, which are also famous around Greece.
Florina, due to its location, is a gateway to many beautiful nearby regions.