We were very happy with our 95 GMC conversion van (2500 chassis), and 16' open trailer for the past 5 years. It was almost perfect for the job. Cheap to buy, simple to maintain, dry bed to sleep in at the track, and dry/secure tool storage at the track. Ours has the 5.7 tbi motor, and the tall rear end gears, which unexpectedly are perfect for towing. Just drop it out of D into 3 and the motor sits right at the 'sweet spot' when pulling at 65-70mph. This setup is for sale now for $4k (van and trailer). I would think you could find deals like this in your part of the country too.

Family needs have put me into a 25' class C motorhome for towing duties, and once the van and/or trailer sells I will probably pick up a 20' enclosed as well, but I will miss having the van as an extra vehicle to drive when a daily driver is in the shop, and for use as a home improvement project tool.