If I'm grasping what you are asking, I'll see if I can clarify this...
The PL/DPL/CTCSS/DCS has nothing to do in "standard" radio system setups with whether a frequency is repeated or simplex (line of sight).
A channel that is the same frequency (168.000) both transmit and receive will be line of sight (with the only exception I can think of being a very rare simplex repeater system -- not commonly used in public safety). These are known as 'simplex' systems. Simplex system ranges are heavily influenced by radio power output, antenna height and location, and geographic features.
A channel that uses a repeater will have one frequency input [TX] and a second frequency output [RX]. (ie: 168.000 TX, 172.550 RX). The exception to this is the above-mentioned simplex repeater system; again, not very common. These systems are commonly known as 'semi-duplex' or 'repeater' systems. These systems are more stable for range and clarity, because all users receive the signal from the central antenna location. Terrain and transmit power still have a influence, especially if your line-of-sight to the antenna is blocked, you are an extreme distance from the antenna, you are using a low-powered radio, or any combination of these factors.
Radio systems using either of these methods MAY or MAY NOT be protected with CTCSS or DCS codes, although most systems nowadays have some kind of tone protection simply due to frequency congestion.
Expected transmission range varies significantly based upon many different factors. We can give you generalities here; you really need to consult a local radio professional who is familiar with your local terrain, etc, to get more reliable answers.
I hope that helps you...
Duster