Hi,
Yes, I think you should use a microcontroller with in-built ADC. Since I use the ATMEGA, I would advocate that. A PIC will do as well though. In this way, you reduce your circuit complexity. Since you brought up "industrial", check the max temperature of the boiler and then, maybe you could use the PT-100. If your temperature was below 150'C, you could use the LM35. For pressure sensor check the MPX4115 and see if it will serve your purpose.
Hope this helps.
Tahmid.