Thanks a bunch! I really appreciate that. Glad you are enjoying them. I added incline /decline tracks as well as a bridge in the update I posted the day before yesterday, check them out if you havent already!
Yes you can tie into the in-game tracks, just use the Map Object Hider mod to hide a section of the in game tracks, then place a placeable switch, then use the straight sections of track to tie back into the in-game tracks. Just watch out that youre not on the mainline when the in game train comes thru!