Although Los Mochis isn't a major city, there are things to do there at least for a weekend or three-day stay over. Here is a good site which shows some of those places. I have spent time in Los Mochis for work and have had the opportunity to hang out there. One thing that is worth noting is the visit to Topolobampo which has a great beach, good restaurants and some interesting bat caves along the road. Also, Los Mochis is famous for good Chinese food.
Tourist Attractions in Los Mochis This website is in English.