This really shouldn't be considered an "alternate" trail to the Vista Loop as there is no other way to finish the official loop from start to finish. To that end, I'm calling this as part of the Vista Loop. This section can be entered either by parking at the parking lot in Crawford Oaks exit off WA-14 or at the Dalles Mountain Road parking lot several miles past the Crawford Oaks exit (the Dalles Mountain road exit is a left-hand turn off of WA-14 right before the road that leads to the Dalles Bridge).
This section is steeper than the official Vista Loop section (eastern half) of the loop, and will be a climb if you decide to ride the noted loop clockwise. You can ride the loop and this section either clockwise OR counter-clockwise. The altitude gain/loss will be the same. Very dry during the summer months, ticks aplenty, so if you're used to biking with four-legged friends, consider not bringing them. This area can also be extremely windy, even by Gorge standards, so uphill climbs can feel like a real slog - can be quite a challenge though! Quiet landscape otherwise.