E to W, then will be skirting the NW of it coming back.
From the east, get gas in Limon about 70 miles east. As long as there are no thunderstorms, Limon is a storm magnet. Once through Denver around Exit 265 Kipling St you should be fine. On your return, you should be good to go. Time of day changes things, but the center of Denver along I70 pretty much sucks all the time. Industrial parks, crappy bars and the like. Your besy bet timing wise would be to traverse I70 before 0600 or after 2200 for traffic. It can be brutal.