Taxis are readily available at the front of each resort ... if you don't see one, ask a Bell Services cast member and they will summon one for you immediately.
Your 5 year old won't require a child safety seat, but your 2 year old sure will. PLEASE restrain your small child when in a small motor vehicle such as a car or SUV (not necessary on large buses). I make my living treating individuals catastrophically injured in motor vehicle accidents, a good number of whom were tiny children held in their parents arms rather than in the proper safety seats. My work is heartbreaking.