To the best of my knowledge you can't. The Gold Edition is well worth the purchase price as you just install and all the patches are included.
As for mods, I'm really enjoying GFO/RSRD right now. Yes, it's a bit short on the realism but that is easily fixed as most of the defects are in the plotting scheme, which automatically gives you enemy boat silhouettes, red for foe, green for friend target colors, ID text that gives away their general course and speed and a velocity vector in front of the enemy, which gives you their exact course and speed.
If you're interested in learning manual targeting, all that stuff is very useful for learning. Once you are semi-convinced that it is sorta possible to hit a target with a manually targeted torpedo, then all you have to do is load up my TMOPlot mod. Load it last.
Then your targets will all be shown as a white dot. There are not friend/foe colors, no velocity vectors, no ID text. Instead, it's plotted simply as a position point. The real guys could write on the chart and unfortunately we can't, but this is a good way to have the info a real captain would have at his disposal.
The nice thing is that you can take the difficulty to the next level of realism without changing the gameplay itself. If you loaded up TMO the enemy is so much smarter that learning is tough. Once you're comfortable with GFO/RSRD/TMOPlot then you're ready to try TMO out to see if you like it.
If you want to run Run Silent Run Deep, I recommend you download v4.01 and Webster's GFO Patch for RSRD 4.01. Load order is GFO, RSRD 4.01, Webster's GFO Patch for RSRD 4.01, and then optionally TMOPlot.
I recommend you keep your mod list very short. Environmental mods especially, mess with the gameplay in bad ways. It's not worth not being able to lock targeting on a ship just to have pretty water. When you're submerged in a fight you aren't looking at the color of the water anyway. Gameplay rules and eye candy drools. That's the rool!
