An open field available to the two new routes for Advent Dark Force, Dasuhiro Plains, is where you will be able to get this trophy. A Float Booster key item is given to you as part of the story scene when you enter that allows you to boost well beyond the second of coverage a normal boost covers, allowing you to traverse this large area with ease.
To get this trophy, you actually need to traverse in one continuous boost for half a minute. This is easily done, granted you take into account the slow turning radius and the enemy spawns. If you start around the northern exit, you can at least glide through the path and then turn right, then turn left to make your way towards the southern end of the map. After passing the mountain on the right and the lake on the left, start turning left to try and cut through to circle around the lake.
Alternatively, on the southern end, you can just find a large enough space and just keep spinning clockwise or counter-clockwise with a wide enough berth to avoid obstacles and enemies and keep in a continuous spin.