I like using small cut frozen corn cobs. Don't worry about thawing. I think the ice method helps with peeling and stopping them from cooking allowing longer soak times. Try throwing a few sticks of butter for flavor and peeling. I prefer Cajunland seasoning. Using liquid boil is great to manage sodium intake since it has no salt or hardly any. I usually take a whole head of garlic and cut the bottom off. The flavor comes out and its easy to get some cloves that way. Throw in whole onions and when it's done just grab one and squeeze the heart out. Really sweet. No need to shake seasoning all over. That should be taken care of in the boil! Make one small batch for the ladies and amateur guys. The experienced men will drink a couple more beers and wait for the final batch. That's where the spice is!!!
http://www.bayouclassiccooking.com/decrkit.html
I think I have a pot like the above link. Seems like I can do a sack and a half at a time. You may be better with a smaller one, but bigger wont be a bad choice.
There's a ton of little things about crawfish boils to remember. It's not just crawfish that's expensive. Veggies, propane, trash bags, plastic bowls and spoons for dips, blah blah blah. A city park is good to use because the trash stays there and is payed by your tax dollars. Bring a hose to use their water if you do.