If you want a trailer for the sole purpose of track days, you can just rent a trailer from Uhaul when need be. They have specific trailers for motorcycles. I bought a '97 4runner for $4000 four wheel drive. The engine is strong, i just need to fix a brake issue. Theres plenty of SUVs in the $4-5k range in good condition. You can find a sub $5k four wheel drive SUV with a trailer hitch. Plenty of room for track goodies, and practical. Then rent a trailer for the occasional track day, you dont seem like the type to be at the track every weekend. Save the extra $5k for a new bike, track gear, and track days.