Having to reset for 5 minutes just to get no snow mobile is not fun or interesting. Being able to decide where you can spawn wouldn't take anything away from the speedrun. Unlike in Minecraft random seed where every seed is different and thus resetting and getting a good seed is a part of the speedrun, rolling the same 1/10 odds every time you start a run is not. In my opinion, there is no downside to this change. This would maybe require a mod or depending on game logic a simple change from somewhere within the game files. I don't know how to accomplish this but just wanted to get this out there.
I've had the same thoughts myself. I spent about 5 hours on runs yesterday and only got two attempts from shelter that I could actually run since snowmobiles kept not spawning at shelter. If a mod or something else allowed for this, I'd support it myself. Curious what others think though.