reverse engineering a proprietary pinout - tips?

I am slowly working out the pinout of a 30-pin connector on the back of a small video camera. I want to work out what features I can, so that I don’t have to use the more fragile and cumbersome plugs on its left side, in a r/c model environment.

However, I feel like Spock who once said, I’m working with stone knives and bear skins. I have just ordered an oscilloscope for the things a DMM can’t help me solve. The 30-pin connector is physically the same as an iPod dock so I got the “iPod Gizmo” breakout from SparkFun.

I got the several GND and +3.75V rails along the bus connector with the battery powered up. I am continuing with the battery out of the camera. I want no unintentional damage, of course.

One of the side plugs is a USB Mini-B for recharging and data transfer. I’ve found by continuity checking where it offers the +5V and GND signals. However, the two data lines may or may not be available on the bus. There are no directly connected pins,

One of the side plugs is a 4-conduit mini jack, also like many audio devices except it’s the smaller jack size. It offers ground, and three RCA jacks for video, left and right audio. I have found that the video ground is 75 ohms away from the system ground, common for traditional video. The other three are not showing up with a common connection.

I will likely have to wait for an oscilloscope or risk plugging a video monitor to the candidate lines, to determine anything else of use in this connector.

Anyone else do work like this, and have some tips on what is risky and what probably won’t damage an expensive device by sniffing?