You can't take out the 12v
system altogether unless you want to do some major rewiring to turn your unit into a 110v-only oddity and never
take it anywhere that doesn't have reliable shore power.
Many people get by just fine without a generator and yet still have a 12v
system. They have an inverter/charger, and can boondock for a few days at a time before they're hooked back up into shore power to recharge their batteries.
Solar can help make up the difference, for keeping the batteries topped up in between camping trips, but solar will not recharge a seriously depleted battery, so it's no substitute for a generator for camping off the grid, more like a supplement to one.
My personal preference would be, if the generator you've got is old and crappy, replace it with a newer and more reliable one. My Interstate comes with a clean, efficient propane-fired Onan 2.5kW generator tucked up between the rear axle and the spare tire, and I wouldn't camp without it.