We took our children camping before they were one. Go
somewhere near home so if it turns pear shaped you can go home and
return in the morning to pack up.
My eldest went on a big trip when he was 18 months and loved it,
although we found afternoon sleeps really hard on all of us.
The youngest has been camping a lot and loves it.
In regards to packing, you need a lot of "stuff" for younger
children as they are less able to keep themselves amused but we use
a plastic tub with a secure lid for each child and they can pack
their toys into that, then stick a label on the inside of the lid
with a list of the contents and check it each night before heading
for bed and you are set.
If you can cope with the idea of going away from home for the
night to a hotel etc, you can cope with camping. Remember to
pack rubbish bags and wet wipes or cloths for cleaning and you are
set.
Have fun and enjoy the great outdoors with your kids, we do and
they can't wait for the next trip!