How hard is it to get a summer research assistant position at a university you don't go to?

I go to a target university far away from where I live. I'm a sophomore and my parents want me to live at home and commute to wherever I work. Would it be difficult to get an RA position at a semi target university closer to where I live? Do some universities have policies where they only hire summer RAs from the same university? I don't mind cold emailing/calling people but I don't want to waste my time if there are university rules against it.