They sell Drain plug adaptors for oil temp sensors. I personally went with Greddy's Oil Filter Sandwich Adapter. Check Greddy's website for details and pricing, it has two ports, so you could even do oil pressure if you wanted.
I went with the Driverside exhaust manifold, and drilled the casting button. It has enough thickness so that it's very easy to tap the hole. After that, it's all down hill and VERY simple. My EGT sensor is still functioning perfectly after more than 2 1/2 years.
If the boost gauge is anything like Greddys, then it's a simple process of T'ing off your boost gauges vacuum line and running the sensor to that, and then the sensors wiring to the gauge.