Avoid westbound out of Denver on Friday afternoons and the weekend. Lots of traffic (including a lot of RV's like yours). As noted, stay in lower gear when heading down the hills. They are long, 7% grades out of the Eisenhower Tunnel and off of Vail Pass. But I-70 is one of the most scenic stretches of interstate around.
Not in a hurry? Another option is to take US 50 west out of Pueblo all the way to Grand Junction. Just one big pass (Monarch) instead of two. More two lane traffic, but plenty of places to pass or be passed. Also quite scenic.
East Coast of Colorado? Well maybe with all the rain we've gotten this month, but not usually ;)
