We stayed at the HRH last time and have just booked our next holiday at the RPR. As soon as you have checked in and have your room keys - you can use the FOTL service. Apparently during peak season (July and August) they are going to limit it to one FOTL for every ride till 3pm, then as many times as you like after that time. But by the time you have been once round everything and had lunch it's probably getting near to 3 anyway. The other trick is to not use it on short line rides then you can use FOTL for that ride if you want to go on again straight after!!
You also get priority seating at all the restaurants too........for example, we liked the Hard Rock Cafe and the queue to get in was always really long - but we just walked up to the front desk, showed our room keys and were shown a table after about a 5 min wait!!! That was super cool!!!