The road mileage between Denver and Reno is 1,052 miles. Salt Lake City is on the driving route and is a good choice as the halfway point since it is 534 miles from Denver and has all of the amenities required as a city to remain in overnight.
the south-western part of Idaho.===
Chiloquin, OR
Forebay, CA.
Crescent, OR
wiinemucca
Pendleton, Oregon, seems to be about halfway between Boise and Tacoma. The Tri-Cities are nearby the halfway point, and they are a larger metro area.
181 miles
Dunlap, CA.
It is roughly 1700 miles from Boise, ID to Chicago, IL. The halfway point between these two cities would be 850 miles, which would put you around Sidney, Nebraska.
Monticello, UT
Fairfax, MO
La Grande, OR
Price, UT
Forsyth, MT
McCloud, CA
Cartago, CA