Slides will usually work correctly from battery.
A #24 Battery will have 70 to 80 AH capacity #27 maybe 90 AH. If you have standard refrig and H/W heater (electronic ignition), water pump etc. you need to figure you're going to need about 25 AH a day. Either standard battery is going to go 2 days tops.
Depending on your converter you will need a 1000 to 2000 watt gen. 45 Amp converter will run on 1000 watt gen, anything bigger will need 1500 to 2000 watt gen (1500 watt are sorta odd-ball, so 2000 is probably better)
Good Luck,
Doug