It's pain in the ass territory...man I remember the blown gasket on my old car. Parts laid out everywhere...unholy nightmare getting it all back together again.
If it's a 4-cylinder, could be done in a few hours. I replaced one on a Isuzu P'up in less than an hour, hardest part of the whole job was getting the timing chain back on.
"V" engines take a little longer. I've done a V-8 Chevy head gasket in 4 hours. Gasket was leaking so bad, the engine would be hydrolocked after it was parked. I had to pull the spark plug from that cylinder to blow the coolant out of it to start it.