difference between a bar fridge and a proper camping one is about 10 hours difference per day your running a generator. Solar panels are expensive so maybe not for you. I have a AGM deep cycle battery, runs the fridge for 8+ hours non stop to -20 degrees. 2-3 hours of charging and away I go.
If i had a bar fridge I would need to run a generator for hours upon hours+ carry crap loads of fuel.
go into a few good camping stores and get some advice, go check out trailblazers and get some info on all the ins and outs.