Depending on what you want to run, and your budget, your options will vary.
You could use a high capacity inverter, and some high capacity deep cycle batteries, and use some
renewable energy sources to replenish them, in addition to a generator, and your vehicle's engine/alternator.
If your talking about running AC it's usually considered impractical.
If you want to run microwaves and TVs and or large continuous draw appliances, you'll have to consider how
much total wattage/amperage you'll need in an average day of use, and then match your power supply and
replenishment strategy to cover that (plus a bit, maybe?).
Cost can be an inhibitor, but you can create systems that will do the very basics, or sky's the limit if you
decide to add solar/wind (yes, some use small wind turbines to recharge their batteries, no idea how well
There are several forum members who can speak to specifics of renewable energy to recharge or to run
their electricity needs. I use my van's engine and a generator to recharge my 2 AGMs while we travel, but
that works for us, because we tend to tour more than stay in one place for days at a time. If we want to
make a brewed cup of coffee, we fire up the generator for a bit, everything else (Tvs, chargers, laptops,
etc.) runs pretty well off 2 small inverters I picked up at Batteries Plus last October. They plug into the 12V
system in the van and draw from the AGMs.
I don't think there's an easy answer, it depends on what you decide you need.