There are a couple thing to be concerned about. First is the tounge weight, the 4Runner allows 500 pounds. This is the weight exhurted on the htich while sitting. If the weight is over 500 pounds, the 4Runner will sag. Second, the weight is over 1,854 pounds. With gas it other items in the cars, it should could reach 2,000 pounds, still well under your limit. The trailer weighs something, I am guessing 1,000 to 1,200 pounds. So my guess is 3,200 pounds. With that kind of weight, it would be helpful to have a weight distrubtion hitch. It will help stop swaying. Third, brakes, you will need brakes on the trailer, it does take awhile to set these things up. Fourth, strain on the transmission and engine. I would recommend a transmission cooler. Also, drive with the ECT button on and the overdrive off. Instead of getting a oil cooler for the engine, I decided to use synthetic oil and keep a eye on the temp. dial.
Also, driving slower is one of the best things to do along with frequent stops. It looks like you have it already hooked up so you have probably addressed these 4 concerns.....