This program can be a bit overwhelming with all its options and the plethora of content. When it comes to route building, it takes time and lots of it. This is a multi-faceted process that requires research, observation, a historical perspective, or backstory for the route, and lots of patience to go with it all. I'm saying this as a long time builder who started building routes back in late 2003/early 2004.
Keep in mind that your first attempts are never the best ones, and like everything else that requires "work", it takes time and effort to get the results you want. This is no different than becoming a top-notch musician or sport player. You need to work at it, practice, and keep working until you get the results. One of the biggest things, which I found to be most helpfu, is modify someone else's route. Download something that suits your interest. Poke around in Surveyor and see how they put things together. Once you get an idea of where things are, add on a baseboard or a siding. While doing this, try to keep the texturing and track laying style the same. This will get you used to track laying and learn the ropes on making track junctions, which can be tricky at times particularly when it comes to big rail junctions and yard areas. There are many really great route builders out there and there is a lot to learn from.
Once you've done this a number of times, perhaps 3 or 4 times, you might try your hand at route building. To build a route, and I've said this many times in the past, you need to plan it out. There are a number of questions that need to be asked before starting. Is this going to be branch line of a major company?, is a good one to start. This helps determine what rolling stock, and buildings you might choose since companies used specific architecture through out their system because it as less expensive to do this for the lesser buildings and save the money for the great terminal station buildings. Having that backstory also keeps the route building on track, no pun intended. With the backstory, you'll know what buildings you want to use and where, and what rolling stock will run on the route. Remember having things planned out, just like having someone else build something, is half the battle. Knowing what you're going to use ahead of time takes the work out the actual route building process. Once you've figured out what the route is, you can then determine a period to run the trains in. This also determines the number of yard tracks, if the branch or line was once busier than it is presently, should you decide on a modern period. Since you are beginning the route building process, consider a modern route due to the complexity of engine terminals, especially for steam servicing, however, this is only a suggestion and you can do as you wish.
As the process continues, you need to look at photographs and maps. They don't have to be your prototype, or even the region you are modeling. These are to give you ideas on engine terminals, track layouts, routes, junctions, etc. I suggest ordinance maps (topographic maps), Bing Bird's Eye photos, and Google Maps. You'll find yourself journeying around the globe gathering ideas for new routes as well as learning from the experts on how to layout a real railroad.
One of the biggest things that needs mentioning is taking a break. When things get stuck, step away from the project and start another, or work on another area of the route. Once things become fresh again, you can go back and continue trekking along as you place buildings, industries, stations, and other stuff. One of the most helpful things is actually taking a short ride on the new route whether the track is only a baseboard or two long or not. I do this often to see what the route is going to look like in that current area, and use this time to fix things I find such things as floating roads, misplaced trees, and crooked buildings, make not of them on a piece of scrap paper, and go back into the editor and fix them. This is also a great opportunity to site down the line and get a feel of what might come up ahead as you look out the window while riding along. As I work on a route, I put a track mark in at the end of the current track and call it EOT. I then let an AI driver navigate to that point as I look out the window. As the tracks become more complex, I sometimes use this opportunity to test the more complex tracks with additional AI traffic as I find it helpful to fix things as I go along rather than trying to fiddle with a complex route that's many miles long. That will come later when the route is complete, and I don't like having to troubleshoot more than I have to at that point.
As you've found, route building is not as easy as one might imagine. The tools are easy to use but the thinking and planning part, and the creative part is the most difficult part of the route building process.
John
.