We highly recommend you consider staying in Boulder overnight, even if you are coming from as close as Denver or Fort Collins. It makes the tournament weekend much more fun! There are plenty of hotels in the area. Here are just three to consider.
The Holiday Inn Express is in North Boulder, one of the hipper neighborhoods of the city with good restaurants and bars (plus a brewery and winery) within walking distance. It is also only five minutes from the fields and you can take a short Uber to central Boulder.
The Hyatt Place Boulder is nicely positioned only six minutes from Pleasant View and at the far east end of Pearl Street in central Boulder. The hotel is new and in a nicely located area of town.
Hampton Inn & Suites North is also only five minutes from the fields but north, in the direction of Longmont and away from Boulder. Breakfast is included, the rooms are good, and there is an indoor pool, all of which helped to make this the #3 hotel in Boulder on TripAdvisor.