omg, i was so happy for you earlier when i read your first post about RPC but couldn't reply until now. that is so awesome!
the main building doesn't have a ton of rooms and i would honestly not get too wound up about where my room was. we have stayed at literally both ends of the hotel and they were each great for different reasons. and the grand suite we had was literally the furthest room from the lounge, and not even on the same floor- and getting to the lounge was still 2 seconds. i can almost promise you that you will have a great room no matter what.
anyway, after 3 RPC stays, my tip is, without question, make time to just soak up the lounge and the main building in general. each subsequent stay reinforced for me how important it is to do this. it never gets old. in particular, have yourself there around or anytime after 3-ish when the live music begins.... that is my absolute favorite. it is just so relaxing up there and then when that music starts, it is just paradise. and you are talking to someone who only listens to rap outside of the GF, so it's not even the kind of music i would ever normally like. but the experience is just great. going around 3 has another advantage, too- snacks are still out till 3:30 and scones are out till 4.

even if you hate scones, have a scone at the lounge- they are like no other scone i have ever had. even the tea at the four seasons in philly AND at the plaza in NYC had scones that stunk in comparison.
ok, this is more than just one tip but one other thing we LOVE to do and have such fond memories of every trip for some reason, is towards the end of our stay, after we have browsed the shops for a few days, setting our sights on what we are interested in, in the evening we have a couple of cocktails or glasses of wine and then we all hit all the shops and buy the things we want to take home. we do this every trip (twice with my parents and once with bff) and have so much fun. and then we go back to the lounge for one more drink.
you will love RPC. i can't wait to read about your reaction to it!