Temple, TX
Hewitt, Texas
Italy, TX
Waco!
The city of Waco, TX was settled in the year 1849. As of the 2010 census, the city of Waco has a total population of 124,805 people. Waco is located in between the cities of Dallas and Austin.
Waco is a a good halfway point for that trip.
Halfway between Waco, TX, and Oskaloosa, IA, is generally around the area of Kansas City, MO. This city is approximately equidistant from both locations and offers various amenities and attractions. Depending on the specific route taken, you might also consider nearby towns like Emporia, KS, or even places in western Missouri as potential halfway points.
Bell, TN
I'll assume you mean the Waco in Texas and the Denver in Colorado. There are at least three others of each. The halfway point is Amarillo. There's only one of that.
Waco, Texas.
Hewit just south of Waco is pretty close
Waco, TX has an area of 95.5sq miles and a population of 126,697.
Sun City in Georgetown, TX is approximately 843 feet above sea level.