Alice is just fine for packing your stuff, but not for hiking around all day in.  Most guys around here have what looks like an "h type" harness with a fire shelter and 32oz canteens along with a butt pack.  That is there 2nd line, I guess it is a lot like military now that I think of it.  Alice for 3rd line, your resupply, clothes wise I mean.  More then likely there will be some sort of rehab unit assigined to the fire where you can get food and other things, don't worry about that. My captain uses a harness type with a camelback on back.  I am not red card so we just fight the wildland for the first day or so while the USDF gets there guys moved around.  When I go to a wildland I use either my bunker pants, very hot, or just the wildland pants and shirt, with the water bottle in the leg pocket.