I think the location and condition of the bike is VERY important.
We've heard reports of it being by a bridge. There are three bridges.........one is a road bridge on CR 225 crossing the S. Arkansas River just below the intersection with US 50. It is visible in the drone-like helicopter footage taken By Channel 4 Denver right after the search ended. If the bicycle had been found there, it would appear as if she was heading away from the house toward somewhere when she became separated from it, but the Ch. 4 video shows no evidence tags on or anywhere near that bridge. The second bridge is also a road bridge, over Fooses Creek on CR 225 below the dam. Since CR 225 only leads to the dam at this spot, if the bicycle had been left there it would appear like she was returning toward her house after her ride. The third bridge is a foot bridge over upper Fooses Creek, on the descent bike trail. It is essentially a high speed, dangerous bicycle bridge, with one way traffic going down (in the direction of her house after completing a ride). Today, we heard scuttlebutt that the bike was found i n a ravine. That third bridge (called Fooses Dam Bridge) is the only one located in a ravine. The Colorado trail, which winds for a good portion along the power line clear cut and/or CR 226, is heavily used by hikers and sightseers, and is very near the mountain bike descent trail at the bridge. Again, if she was separated from her bike at this bridge, she would have been returning to her house at the end of her ride. It is highly unlikely that a perp would have carried bike with locked wheels all the way up Colorado trail to the Fooses Dam Bridge, but it is very likely that a perp could have driven to the road bridge and dumped the bike quickly. IMO
The attached Google Earth Aerial View was generated entirely by Google tools, and shows the location of all three bridges and their relationship to SM's house. The red circle indicates the extent of the second day (big) search, as described by the sheriff in a news conference. I believe it was early in this search when the bike when rumors of a bike being found first arose.