Wandering bitch

My girl is 2 years old. Friendly bordercollie/hunterway. I know she needs exercise and I do this every day. I want to let her loose on our property but I have to tie her up if she’s outside. Otherwise she’ll just wander. She has found a playmate 2km away but if she goes there they feed her and lock her up for the night. They don’t answer my text.
What should I do. I know I’m in the wrong as it’s my dog that’s wandering

You'd best invest in some fencing to keep her in. Wandering dogs arent always welcome and theres the chance she could be run over or shot.