Toyota Repair: 91 4X4 Possible head gasket?, blown head gasket, rad cap

Question
I have a 91 4X4 pickup with the 4cyl eng.  It will start and run until it gets up to temp, then will run rough and surge.  When I look at the oil, I can see some milkiness suggesting that there is coolant getting into the oil.  Also I can see oil on the rad cap suggeting that there is oil getting into the coolant.  When the truck does get up to temp, there is remnants of coolant coming out of the exhaust pipe.  
I am figuring that I probably have a blown head gasket, but with these symptoms, do you think that it may be a larger problem - Cracked Head?, Cracked Block?, Other?  

Answer
Cracked blocks are very rare, cracked cylinder heads are not so there is that possibility, the only way to be sure is to remove the cylinder head and have the head tested at a machine shop.
Before doing anything major you should have a combustion leak test done this will show if there are any hydrocarbons in the coolant when the engine is at operating temp.
I have seen many cases where the timing chain has worn through the timing cover and this enables coolant to enter into the oil and also oil to get into the coolant, something to watch out for especially if the block test turns out good.