I have a PSPICE file that contains approximately 200+ transistors. Naturally, simulating the whole circuit everytime I make a change takes a while. Is there anyway to run a simulation measuring only the voltage at a specified node?
Unfortunately it is not (automatically) possible as far as I know to simulate only one node. But that doesn't mean there aren't things you can do!
Controlling the step size
By controlling the time steps you can sometimes significantly reduce the number of timepoints simulated. Start by reducing the stop time of the simulation as much as possible. The transient timestep itself is usually controlled by two things: the truncation error and breakpoints. Truncation error can be controlled by the TRTOL option, but it will also influence accuracy. Breakpoints are added by Spice when using voltage sources for hard edges, like pulsed voltage sources (PULSE). So if the circuit you're interested in is relatively slow, make sure you're not using a fast clock signal somewhere else as the clock will generate a lot of breakpoints.
Dividing up the circuit in smaller blocks and designing/testing them separately is good practice. Staying away from big circuits until necessary is the best remedy.
Change the simulation type
You don't always need a transient analysis (it is the slowest of the bunch). Always consider whether or not you really need it. Is your circuit digital, then consider using logic simulators. Are time effects really necessary? Maybe an AC or DC analysis is enough.
Model parts of your circuit
You may be able to model big parts in your circuit with a small amount of components. In the most extreme case, you can replace a complete voltage or current waveform with a single independent voltage or current source. You could export the trace, then write that simulated trace data in a file to be used by an independent source. The source will linearly interpolate the data points in the file, giving a good approximation.
Modeling parts of your circuit typically involves using ideal components (controlled sources, res, cap, switches, etc.) to approximate behavior. However it can sometimes lead to convergence issues if some components are too ideal (eg. switches).
This is all I can think of with the limited information provided.