Barbarossa Brawl - How on earth do you survive 20 minutes?

I've managed 18 mins a few times, but honestly after blue joins in it's just so hopeless it's not even particularly fun.

I start off slowing down to 1.0, then place two TCs, one by the stone and one by the gold, along with a market. I send my scout up to get the cumans, and bring them down to my castle. I build houses along the northwest and east bridges, then build a castle on the northwest bridge.

I make 10 TKs at the initial castle, and that + the cumans seems to be enough to survive the onslaught of Knights from green with some units left over, sometimes. Sometimes they all just die.

I make about 10 vills at each TC, for food, gold, and stone. I've yet to even get close to running out of wood considering the food limit, so I've not been focusing on that.

I then build a castle on the east bridge, and garrison both castles with 5 TKs. I then basically sit there sniping the seige with the castles to fend off orange and most of purple.

And then I die. Blue comes and sweeps through and destroys the TC. If I try to deal with blue, orange and purple overwhelm me. By this point I'm out of stone, so it's not like I can just build more castles.

I've tried making pikemen from an array of barracks, but I just end up too low on food and they basically do nothing. I've tried going to imp for ETK, but that just uses way too many resources to be even slightly viable. I've tried walling all access, but that just makes the AI go a bit weird and go straight for my vills instead of attempting to take down the castles.

I've got absolutely no idea what on earth I should be doing here, but there just seems to be no way for a noob to get even close to 20 minutes. The blue onslaught comes early enough that it will always overwhelm me, and by that point orange has managed to get my castle down and raided through my gold vills.

Does anyone have any nice consistent strats to get the 20 mins? I'm honestly not really having much fun with this, especially considering there's a ticking clock on the event and I need to get it done for the pretzel mod.

I hate timed unlocks.