I, of course, work on somebody else's route: Mojave Sub in 2012. I add in things like: asphalt parking lots, gravel-covered barn yards, etc. I use textures heavily as well as ground tamping.
I add in my own amenities: lakes, rivers, ranches, farms, dams, trees, schools, parks, churches, horse-drawn wagon animation, operating aircraft, boats, tree orchards, summer cottages, an island, train stations, upgraded railroad yards and airports. A great deal of ground had to be excavated deep and textured with mud, sandstone and sand soil, to put in my reservoir, about 7 miles in circumference, with dam in an otherwise flat piece of southern California Kern County desert. I prefer LOTS of 3-D static objects as people, animals, vehicles and the like.
My trains and cars run over the narrow mid-section of the reservoir via bridges which I installed. This is Highway 58 from Bakersfield to Mojave and the former SP now UP train line. I even have Vulcan's float plane landing and taking off on a closed loop around this man-made lake near the lake-side marina.
I have actually driven this piece of road in the real world several times. I think BNSF trains also run this Mojave Sub nowadays.
Cutting and replacing train boards from older incremental saves has become a regularity with me. I have now made it a habit to inspect the entire layout closely especially after a lot of texture edits and ground edits.
It is also making sense now to edit the layout in one direction only as starting from the east portal and working toward the west portal. Sometimes it is just easier to "saw off" a good half of an older save to replace that half that went bad after heavy texture work down the train line on the other half. I have to use Merge Routes/Layers a lot for this. I try to cut the route (deleting a line of ground squares) in half where there are relatively few splines crossing the train board borders or where there is an remote rural area not heavily populated as in a large city borders as these are tedious to tie up again after a merge routes repair. I use temporary pieces of track to mark the squares to be removed and replaced so as to avoid confusion. The track used as place marks shows up as blue lines in map view overhead.