Just to summarize your fit issues:
On the road bike you tried the bars were set too low, and probably too far forward, leading to a feeling of being way down.
On your own Mt bike you found the bars are too high, and perhaps not far enough forward.
This gives you a clear sense of where you want the bars. The remaining question is which part of the bars?
If you wind up with drop bars, you should assume that you will spend most of your time in one of two positions: with your hands on the hoods, and with your hands on the tops - either on the flat or on the curved part. For touring, you're unlikely to spend a whole lot of time with your hands in the remaining two positions, except for a change. These positions are all the way forward in the drops, where you can still reach the brakes, and near the ends of the bars. The main reason you would want to use these positions are for better aerodynamics when fighting a headwind, and descending, and, as I said, for a change.
To set it up for touring, the hoods should not feel all that far away. This means a shorter stem (or an adjustable one pulled back further) than you would see on an Mt bike that fits. Or better still, a shorter top tube on the frame. Don't be afraid to go a size "too small" on the frame and use a long seat post and combination of steerer and stem to bring the saddle and bars up high enough. The shorter top tube is what you'll find in the women's specific designs. But Trek doesn't make the 520 or an equivalent in WSD.
