The Camplite 13 QBB shows a single axle 3000 lb GVWR trailer which equates to 1500 lbs per tire as a minimum.
Maxxis ST8008 has the best rep of all the ST tires at this time across the trailering forums and has a ST185/80-13 C load range at 1460 lbs per tire that will work.
Maxxis also has a commercial grade U-168 Bravo LT5.50R13 in a 80 psi tire at 1480 lbs capacity and a same size 90 psi rated tire at 1610 lbs capacity.
Check your wheels for proper width and pressure ratings for each tire. Both tires are very popular with the overall trailering crowd including RV folks.
Or take a chance on the advertised much improved other ST tires with a nylon belt under the tread.
ST tires are limited to 65 mph. A small 13" tire at that speed is rotating much higher rates than it bigger brothers. Keep the speed down.
The single axle light weight trailer isn't as hard on tires as a heavy multi axle trailer. Many folks go with a 13 "P tire with good success, that has the proper load capacity.