If she still fits in a travel cot, these make excellent temporary containment facilities.
The IKEA Antilop highchair was our saviour - the legs come off dead easily and the seat bit is not much bigger than a normal folding portable "seat that needs a chair to be strapped onto" thingy.
Take the tray and a couple of sucker toy things. Trying to feed a crawling toddler at ground level is tricky at best, dangerous at worst (camp stoves etc stay hot for a long time) you can also use as another temporary containment facility whilst erecting tent etc.
If all else fails, leave toddler strapped in car while you put tent up. Basically, they WILL choose the moment when you're trying to stop the entire structure blowing into the next field to make a run for nearest body of water / attempt to drink meths / crawl between peg and mallet.
Small blow up paddling pool = hours of fun plus useful for hosing mud off bathing at the end of particularly adventurous face plants in muddy ditches manouvres.
If too big for travel cot, one of those air mattresses with sides will help minimize rolling-off-mat-onto-cold-groundsheet issues.
Positives - you should still find she'll sleep okay (might be a bit later in the evenings) and she'll have a blast even if your nerves are shredded...
This year I'm going to be attempting camping with toddler AND newborn, now that should be REALLY interesting!
Good luck 