An open border policy with Mexico that allows for full freedom of movement and unrestricted free trade that will greatly help both economies along with enforcing the right of self expression for all Americans, sounds like things the Republicans would do if they actually believed what they preach or what Democrats would be doing if they had half a spine.
A similar policy with Canada would likely lead to similar effects, as while it is more open than that of Mexico there are still significant economic limitations imposed by travel restrictions. You are however unlikely to get Canada or Mexico to agree to complely unrestricted trade given the history of Amarican companies annexing their northern neighbors.
