Bear Creek area is in extreme southwest corner of the county. I don't think they would have gone to Newton or Van Buren County to marry, but just on a chance they might have, I checked in these two counties and didn't find a marriage for Richard Montgomery in either one.
The country around Bear Creek west to Newton County is way too rugged for travel back in the 1870s. Van Buren County wouldn't have been quite as bad, but not a whole lot better. But it would have been way too far to travel when Marshall was so close by.And Pope County County where I live is much farther away than either one of the other two counties.