Thanks to Gary Smith for scouting the Extended Yakima River Tour, and Cathy for providing support and a steady stream of messages about the route. Here's the summary from the ride:
Control 2 - Prosser - Conoco Food Mart hours 0500 - 2300
Control 3 - Toppenish - Safeway hours 0600 - 2400
Distance 100.1 km L N. Track R
There is no street sign on N. Track - but, it is the first left after crossing the train tracks. The road changes name and is Asotin Way on the right - where there is a sign
Control 4 - Wiley Mkt
No restroom facilities. Minimal food available. Recommend eating in Union Gap before the control or after getting back to Yakima
Bike path from Yakima to Selah
distance 157.4 km - turn left on Gordon
The street sign is turned 90 deg. after you go through the 1 lane tunnel, take a left. the street sign points to Gordon for continuing straight, and 6th for turning left.
The start of the bike path is not obvious. the barriers are not color-coded, there are no signs, nothing to say "HERE".
Distance 157.2 no facilities or places to stop after leaving Selah until you reach Ellensburg, about 50+ km.
Control 5 Ellensburg
The Safeway has seats inside if you need to rest.
The person running the AM/PM didn't want me loitering inside his shop. There were no seats either inside or outside. If someone wants to rest, they might check across the street (google maps indicates a Chevron; other sources a 76). The Sonic about 3 blocks before the control - near the intersection of 1st and Nob Hill - is open until 2400 (the organizer enjoys the burgers).
Distance 310.4 - the control in Zillah
Street sign shows the name as 1st. The next turn into the Chevron is not named Zillah West Rd either, but i don't think that matters. The service station is hard to miss.
The road is being resurfaced just as you get into Grandview - for 2-3 blocks.
Control 8 - Prosser Highway Rest Stop services
the Chevron has seats inside that are comfortable for napping.