I have a Skylark and experienced sway problems between 55-60 mph. I installed a Reese Friction Sway control and no more problems.
Cost is about $55 and is an easy DIY install on the trailer, but you will need a weld shop to add the sway ball on your ball bracket. We tow with a 2012 Honda Pilot 6 cyl and get between 10 and 14 mpg depending upon speed and terrain towing the Skylark. We previously towed it with a Mazda Tribute, but teh small fuel tank meant you were stopping every 1-1/2 hours for fuel.