If it's a new Diesel Pusher with a residential fridge, you have no problem going down the road. The fridge will be running on the inverter. The batteries and alternator will be more then enough to power the fridg. You may not be able to run your roof airs on the alternator (we can run 2 of the 4 off the inverters and alternators). When we get to a campsite,the batteries are fully charged and will last to morning before we have to run the generator. Yours may not last as long, but the batteries should be fully charged when you stop for the night, even with the fridge running.