Scandinavia is all about summer. In July and August the days are longest, the water is swimmable and nature is at its best, in the far north the sun barely sets. It's exactly the season the Horizon was built for.
And unlike a holiday home or hotel, you don't need to book months ahead. With an off-grid campervan you stay freely in nature, so you're not at the mercy of fully booked campsites. One open week in the calendar is all it takes to go.