if you want to stay larger than stock, the easiest size to find a wide selection in is going to probably be 265/60/18.. the fortera triple treds are super highly rated, but the price tag is what steered me away from them, that and if your alignment is out at all, they will wear like crazy

id reccomend looking for a set of old tacoma wheels, or just regular steel wheels that will fit dependnig what you want to spend maybe pick up a cheaper set of "nice" wheels, 15 or 16 will be easiest to find tires in, and that way you dont end up having to swap the tires back and forth, you can just swap the rims, much faster and less $$ in labor