Houston spent time talking with a couple of different types of players at each school.
"At Colorado, I got to hang out a little bit with the two QBs, Nick Hirschman and Tyler Hansen, and at Iowa, I was with a couple of offensive lineman," said Houston. "I got to see the academic side and the football side at each school."
The trip capped off a busy spring that saw him visit double-digit schools in the past couple of weeks.
Houston, who has numerous offers spreading the country, said he thinks more offers will come in the weeks head.
"I had a good time up at Oregon State and I know that (former DLS teammate and Oregon State signee) Dylan Wynn has been putting in his two cents there," said Houston. "They want to come see me throw in the spring. And Duke and Texas Tech, I guess those will be the three that said ‘we have to come out and see you throw'. So we'll see how it all goes."
Houston has set summer as the time he'd like to decide.
"I'd like to announce in June or July, which is in like a month or two, but I'll have to come to a conclusion later because I haven't really started to narrow things down," said Houston. "I have eight favorites, all the schools that have offered me."
Houston said Colorado has been by the school and that several other schools, including ones that have offered like UCLA, Washington and San Diego State, will be by in when the Spartans start spring ball.
The four-star passer has only two more camps on the docket for the spring.
"I'll be going to the Elite 11 and the Nike Camp at Stanford," said Houston.
The California Junior of the Year by GoldenStatePreps.com, Houston helped the Spartans to their second straight CIF State Open Division title, and has won 27 straight games as a starting quarterback.
On the year, Houston was 102-for-153 for 1,922 yards with 20 touchdown passes and just four interceptions. He played into the second half in only a handful of games and had a QB rating of 138. He also rushed for 11 touchdowns.